diff --git a/docs/pyagentspec/source/_components/all_components.json b/docs/pyagentspec/source/_components/all_components.json
index 44394b59..a0ce07bd 100644
--- a/docs/pyagentspec/source/_components/all_components.json
+++ b/docs/pyagentspec/source/_components/all_components.json
@@ -119,6 +119,22 @@
                 "path": "pyagentspec.llms.ocigenaiconfig.OciGenAiConfig",
                 "name": "pyagentspec.llms.OciGenAiConfig"
             },
+            {
+                "path": "pyagentspec.llms.geminiconfig.GeminiConfig",
+                "name": "pyagentspec.llms.GeminiConfig"
+            },
+            {
+                "path": "pyagentspec.llms.geminiauthconfig.GeminiAuthConfig",
+                "name": "pyagentspec.llms.GeminiAuthConfig"
+            },
+            {
+                "path": "pyagentspec.llms.geminiauthconfig.GeminiAIStudioAuthConfig",
+                "name": "pyagentspec.llms.GeminiAIStudioAuthConfig"
+            },
+            {
+                "path": "pyagentspec.llms.geminiauthconfig.GeminiVertexAIAuthConfig",
+                "name": "pyagentspec.llms.GeminiVertexAIAuthConfig"
+            },
             {
                 "path": "pyagentspec.llms.ociclientconfig.OciClientConfig",
                 "name": "pyagentspec.llms.OciClientConfig"
diff --git a/docs/pyagentspec/source/_components/llm_config_tabs.rst b/docs/pyagentspec/source/_components/llm_config_tabs.rst
index d26b9ce0..7053601c 100644
--- a/docs/pyagentspec/source/_components/llm_config_tabs.rst
+++ b/docs/pyagentspec/source/_components/llm_config_tabs.rst
@@ -37,6 +37,20 @@
                 client_config=client_config,
             )
 
+    .. tab:: Gemini
+
+        .. code-block:: python
+
+            from pyagentspec.llms import GeminiConfig
+            from pyagentspec.llms.geminiauthconfig import GeminiAIStudioAuthConfig
+
+            llm_config = GeminiConfig(
+                name="Gemini Flash",
+                model_id="gemini-2.5-flash",
+                # The runtime can read GEMINI_API_KEY from the environment.
+                auth=GeminiAIStudioAuthConfig(name="gemini-aistudio-auth"),
+            )
+
     .. tab:: vLLM
 
         .. code-block:: python
diff --git a/docs/pyagentspec/source/agentspec/json_spec/agentspec_json_spec_26_2_0.json b/docs/pyagentspec/source/agentspec/json_spec/agentspec_json_spec_26_2_0.json
index 9df93bda..127bce73 100644
--- a/docs/pyagentspec/source/agentspec/json_spec/agentspec_json_spec_26_2_0.json
+++ b/docs/pyagentspec/source/agentspec/json_spec/agentspec_json_spec_26_2_0.json
@@ -243,6 +243,46 @@
         }
       ]
     },
+    "GeminiAIStudioAuthConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiAIStudioAuthConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ]
+    },
+    "GeminiAuthConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiAuthConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ]
+    },
+    "GeminiConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ]
+    },
+    "GeminiVertexAIAuthConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiVertexAIAuthConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ]
+    },
     "HandoffMode": {
       "description": "Controls how agents in a Swarm may delegate work to one another.\n\nThis setting determines whether an agent is equipped with:\n\n  * *send_message* \u2014 a tool for asking another agent to perform a sub-task and reply back.\n\n  * *handoff_conversation* \u2014 a tool for transferring the full user\u2013agent conversation to another agent.\n\nDepending on the selected mode, agents have different capabilities for delegation and collaboration.",
       "enum": [
@@ -2856,6 +2896,243 @@
       "type": "object",
       "x-abstract-component": false
     },
+    "BaseGeminiAIStudioAuthConfig": {
+      "additionalProperties": false,
+      "description": "Authentication settings for Gemini via Google AI Studio.",
+      "properties": {
+        "id": {
+          "title": "Id",
+          "type": "string"
+        },
+        "name": {
+          "title": "Name",
+          "type": "string"
+        },
+        "description": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Description"
+        },
+        "metadata": {
+          "anyOf": [
+            {
+              "additionalProperties": true,
+              "type": "object"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "title": "Metadata"
+        },
+        "api_key": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Api Key"
+        },
+        "$referenced_components": {
+          "$ref": "#/$defs/ReferencedComponents"
+        },
+        "component_type": {
+          "const": "GeminiAIStudioAuthConfig"
+        }
+      },
+      "required": [
+        "name"
+      ],
+      "title": "GeminiAIStudioAuthConfig",
+      "type": "object",
+      "x-abstract-component": false
+    },
+    "BaseGeminiAuthConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/GeminiAIStudioAuthConfig"
+        },
+        {
+          "$ref": "#/$defs/GeminiVertexAIAuthConfig"
+        }
+      ],
+      "x-abstract-component": true
+    },
+    "BaseGeminiConfig": {
+      "additionalProperties": false,
+      "description": "Configure a connection to a Gemini LLM (AI Studio or Vertex AI).",
+      "properties": {
+        "id": {
+          "title": "Id",
+          "type": "string"
+        },
+        "name": {
+          "title": "Name",
+          "type": "string"
+        },
+        "description": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Description"
+        },
+        "metadata": {
+          "anyOf": [
+            {
+              "additionalProperties": true,
+              "type": "object"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "title": "Metadata"
+        },
+        "default_generation_parameters": {
+          "anyOf": [
+            {
+              "type": "null"
+            },
+            {
+              "$ref": "#/$defs/LlmGenerationConfig"
+            }
+          ],
+          "default": null
+        },
+        "retry_policy": {
+          "anyOf": [
+            {
+              "type": "null"
+            },
+            {
+              "$ref": "#/$defs/RetryPolicy"
+            }
+          ],
+          "default": null
+        },
+        "model_id": {
+          "title": "Model Id",
+          "type": "string"
+        },
+        "auth": {
+          "$ref": "#/$defs/GeminiAuthConfig"
+        },
+        "$referenced_components": {
+          "$ref": "#/$defs/ReferencedComponents"
+        },
+        "component_type": {
+          "const": "GeminiConfig"
+        }
+      },
+      "required": [
+        "auth",
+        "model_id",
+        "name"
+      ],
+      "title": "GeminiConfig",
+      "type": "object",
+      "x-abstract-component": false
+    },
+    "BaseGeminiVertexAIAuthConfig": {
+      "additionalProperties": false,
+      "description": "Authentication settings for Gemini via Google Vertex AI.",
+      "properties": {
+        "id": {
+          "title": "Id",
+          "type": "string"
+        },
+        "name": {
+          "title": "Name",
+          "type": "string"
+        },
+        "description": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Description"
+        },
+        "metadata": {
+          "anyOf": [
+            {
+              "additionalProperties": true,
+              "type": "object"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "title": "Metadata"
+        },
+        "project_id": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Project Id"
+        },
+        "location": {
+          "default": "global",
+          "title": "Location",
+          "type": "string"
+        },
+        "credentials": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "additionalProperties": true,
+              "type": "object"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Credentials"
+        },
+        "$referenced_components": {
+          "$ref": "#/$defs/ReferencedComponents"
+        },
+        "component_type": {
+          "const": "GeminiVertexAIAuthConfig"
+        }
+      },
+      "required": [
+        "name"
+      ],
+      "title": "GeminiVertexAIAuthConfig",
+      "type": "object",
+      "x-abstract-component": false
+    },
     "BaseInMemoryCollectionDatastore": {
       "additionalProperties": false,
       "description": "In-memory datastore for testing and development purposes.",
@@ -3015,6 +3292,9 @@
     },
     "BaseLlmConfig": {
       "anyOf": [
+        {
+          "$ref": "#/$defs/GeminiConfig"
+        },
         {
           "$ref": "#/$defs/OciGenAiConfig"
         },
@@ -7080,6 +7360,18 @@
           {
             "$ref": "#/$defs/BaseFlowNode"
           },
+          {
+            "$ref": "#/$defs/BaseGeminiAIStudioAuthConfig"
+          },
+          {
+            "$ref": "#/$defs/BaseGeminiAuthConfig"
+          },
+          {
+            "$ref": "#/$defs/BaseGeminiConfig"
+          },
+          {
+            "$ref": "#/$defs/BaseGeminiVertexAIAuthConfig"
+          },
           {
             "$ref": "#/$defs/BaseInMemoryCollectionDatastore"
           },
@@ -7564,6 +7856,66 @@
         }
       }
     },
+    "VersionedGeminiAIStudioAuthConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiAIStudioAuthConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ],
+      "properties": {
+        "agentspec_version": {
+          "$ref": "#/$defs/AgentSpecVersionEnum"
+        }
+      }
+    },
+    "VersionedGeminiAuthConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiAuthConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ],
+      "properties": {
+        "agentspec_version": {
+          "$ref": "#/$defs/AgentSpecVersionEnum"
+        }
+      }
+    },
+    "VersionedGeminiConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ],
+      "properties": {
+        "agentspec_version": {
+          "$ref": "#/$defs/AgentSpecVersionEnum"
+        }
+      }
+    },
+    "VersionedGeminiVertexAIAuthConfig": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/BaseGeminiVertexAIAuthConfig"
+        },
+        {
+          "$ref": "#/$defs/ComponentReference"
+        }
+      ],
+      "properties": {
+        "agentspec_version": {
+          "$ref": "#/$defs/AgentSpecVersionEnum"
+        }
+      }
+    },
     "VersionedInMemoryCollectionDatastore": {
       "anyOf": [
         {
@@ -8353,6 +8705,18 @@
     {
       "$ref": "#/$defs/VersionedFlowNode"
     },
+    {
+      "$ref": "#/$defs/VersionedGeminiAIStudioAuthConfig"
+    },
+    {
+      "$ref": "#/$defs/VersionedGeminiAuthConfig"
+    },
+    {
+      "$ref": "#/$defs/VersionedGeminiConfig"
+    },
+    {
+      "$ref": "#/$defs/VersionedGeminiVertexAIAuthConfig"
+    },
     {
       "$ref": "#/$defs/VersionedInMemoryCollectionDatastore"
     },
diff --git a/docs/pyagentspec/source/agentspec/language_spec_nightly.rst b/docs/pyagentspec/source/agentspec/language_spec_nightly.rst
index 62ef7e28..fdbfa2b8 100644
--- a/docs/pyagentspec/source/agentspec/language_spec_nightly.rst
+++ b/docs/pyagentspec/source/agentspec/language_spec_nightly.rst
@@ -837,6 +837,58 @@ Client configuration that should be used if users want to use resource principal
     class OciClientConfigWithResourcePrincipal(OciClientConfig):
         auth_type: Literal["RESOURCE_PRINCIPAL"] = "RESOURCE_PRINCIPAL"
 
+Gemini
+^^^^^^
+
+This class of LLMs refers to the Gemini family of models offered by `Google <https://gemini.google/about/>`_.
+Google offers Gemini through two services: `AI Studio <https://aistudio.google.com/welcome/>`_ and `Vertex AI <https://cloud.google.com/vertex-ai/>`_.
+
+.. code-block:: python
+
+   class GeminiConfig(LlmConfig):
+     model_id: str
+     auth: SerializeAsAny[GeminiAuthConfig]
+
+.. code-block:: python
+
+   class GeminiAuthConfig(Component, abstract=True):
+     pass
+
+AI Studio uses API key-based authentication:
+
+.. code-block:: python
+
+   class GeminiAIStudioAuthConfig(GeminiAuthConfig):
+     api_key: SensitiveField[Optional[str]] = None
+
+When ``api_key`` is not specified, runtimes may try to load it from the ``GEMINI_API_KEY``
+environment variable.
+
+Meanwhile, the Vertex AI service can be authenticated with Google Cloud credentials. These credentials can be provided with a `service account JSON key <https://docs.cloud.google.com/iam/docs/keys-create-delete/>`_
+either inline or through a local file path. When omitted, runtimes may rely on Google Application Default Credentials (ADC), such as
+the ``GOOGLE_APPLICATION_CREDENTIALS`` environment variable, credentials made available through the local Google Cloud environment,
+or an attached service account. Even with ADC, the ``project_id`` may still need to be provided explicitly when it cannot be
+resolved from the local Google Cloud configuration:
+
+.. code-block:: python
+
+   class GeminiVertexAIAuthConfig(GeminiAuthConfig):
+     project_id: Optional[str] = None
+     location: str = "global"
+     credentials: SensitiveField[Optional[Union[str, Dict[str, Any]]]] = None
+
+Here, ``credentials`` accepts either a local file path (``str``) to a Google Cloud JSON
+credential file, such as a service-account key file, or an inline ``dict`` containing the
+parsed JSON contents of that file.
+
+See `Using Gemini API keys <https://ai.google.dev/gemini-api/docs/api-key>`_,
+`Application Default Credentials <https://cloud.google.com/docs/authentication/application-default-credentials>`_,
+and `Create and delete service account keys <https://cloud.google.com/iam/docs/keys-create-delete>`_
+for more details.
+``GeminiConfig.auth`` stays inline when serialized. If ``api_key`` or ``credentials`` of the auth object is
+specified, only that sensitive field is externalized. Otherwise, if ``api_key`` or ``credentials`` is
+unset, that field serializes as ``null``.
+
 Tools
 ~~~~~
 
@@ -2867,6 +2919,10 @@ See all the fields below that are considered sensitive fields:
 +----------------------------------+--------------------+
 | OpenAiConfig                     | api_key            |
 +----------------------------------+--------------------+
+| GeminiAIStudioAuthConfig         | api_key            |
++----------------------------------+--------------------+
+| GeminiVertexAIAuthConfig         | credentials        |
++----------------------------------+--------------------+
 | OciClientConfigWithSecurityToken | auth_file_location |
 +----------------------------------+--------------------+
 | OciClientConfigWithApiKey        | auth_file_location |
@@ -2890,6 +2946,10 @@ See all the fields below that are considered sensitive fields:
 | StreamableHTTPmTLSTransport      | ca_file            |
 +----------------------------------+--------------------+
 
+For example, ``GeminiAIStudioAuthConfig.api_key`` or
+``GeminiVertexAIAuthConfig.credentials`` may become references while the enclosing
+``auth`` component remains inline.
+
 
 For example, the following component produced using the `pyagentspec` SDK:
 
diff --git a/docs/pyagentspec/source/api/llmmodels.rst b/docs/pyagentspec/source/api/llmmodels.rst
index b4eb69ec..c1db63fd 100644
--- a/docs/pyagentspec/source/api/llmmodels.rst
+++ b/docs/pyagentspec/source/api/llmmodels.rst
@@ -66,6 +66,25 @@ OpenAI Models
 .. autoclass:: pyagentspec.llms.openaiconfig.OpenAiConfig
     :exclude-members: model_post_init, model_config
 
+Gemini Models
+^^^^^^^^^^^^^
+
+.. _geminiauthconfig:
+.. autoclass:: pyagentspec.llms.geminiauthconfig.GeminiAuthConfig
+    :exclude-members: model_post_init, model_config
+
+.. _geminiaistudioauthconfig:
+.. autoclass:: pyagentspec.llms.geminiauthconfig.GeminiAIStudioAuthConfig
+    :exclude-members: model_post_init, model_config
+
+.. _geminivertexaiauthconfig:
+.. autoclass:: pyagentspec.llms.geminiauthconfig.GeminiVertexAIAuthConfig
+    :exclude-members: model_post_init, model_config
+
+.. _geminiconfig:
+.. autoclass:: pyagentspec.llms.geminiconfig.GeminiConfig
+    :exclude-members: model_post_init, model_config
+
 OciGenAi Models
 ^^^^^^^^^^^^^^^
 
diff --git a/docs/pyagentspec/source/changelog.rst b/docs/pyagentspec/source/changelog.rst
index d879ad1d..55190ee0 100644
--- a/docs/pyagentspec/source/changelog.rst
+++ b/docs/pyagentspec/source/changelog.rst
@@ -105,6 +105,13 @@ New features
 
   For more information read the :doc:`adapter page <adapters/wayflow/index>`.
 
+* **Gemini LLM configuration support**
+
+  Added ``GeminiConfig`` together with ``GeminiAIStudioAuthConfig`` and
+  ``GeminiVertexAIAuthConfig`` to represent Gemini models in Agent Spec.
+
+  For more information read the :doc:`API Reference <api/llmmodels>`.
+
 * **Added Microsoft Agent Framework adapter to pyagentspec:**
 
   The Microsoft Agent Framework adapter is now available as part of ``pyagentspec``.
diff --git a/docs/pyagentspec/source/code_examples/howto_llm_from_different_providers.py b/docs/pyagentspec/source/code_examples/howto_llm_from_different_providers.py
index 5374d3d1..0909a509 100644
--- a/docs/pyagentspec/source/code_examples/howto_llm_from_different_providers.py
+++ b/docs/pyagentspec/source/code_examples/howto_llm_from_different_providers.py
@@ -85,6 +85,42 @@
 )
 # .. openai-end
 
+# .. gemini-aistudio-start
+from pyagentspec.llms import GeminiConfig
+from pyagentspec.llms.geminiauthconfig import GeminiAIStudioAuthConfig
+
+generation_config = LlmGenerationConfig(max_tokens=256, temperature=0.7, top_p=0.9)
+
+llm = GeminiConfig(
+    name="gemini-aistudio-flash",
+    model_id="gemini-2.5-flash",
+    auth=GeminiAIStudioAuthConfig(
+        name="gemini-aistudio-auth"
+        # Optional: if api_key is omitted, runtimes may load GEMINI_API_KEY from the environment.
+    ),
+    default_generation_parameters=generation_config,
+)
+# .. gemini-aistudio-end
+
+# .. gemini-vertex-start
+from pyagentspec.llms.geminiauthconfig import GeminiVertexAIAuthConfig
+
+generation_config = LlmGenerationConfig(max_tokens=256, temperature=0.4, top_p=0.95)
+
+llm = GeminiConfig(
+    name="gemini-vertex-flash",
+    model_id="gemini-2.0-flash-lite",
+    auth=GeminiVertexAIAuthConfig(
+        name="gemini-vertex-auth",
+        # Often still required even when ADC supplies the credentials.
+        project_id="my-gcp-project",
+        location="global",
+        # Optional: explicit credentials can be provided when ADC is not available.
+    ),
+    default_generation_parameters=generation_config,
+)
+# .. gemini-vertex-end
+
 # .. ollama-start
 from pyagentspec.llms import OllamaConfig
 
@@ -168,6 +204,34 @@
     default_generation_parameters=generation_config,
 )
 
+from pyagentspec.llms import GeminiConfig
+from pyagentspec.llms.geminiauthconfig import GeminiAIStudioAuthConfig, GeminiVertexAIAuthConfig
+
+generation_config = LlmGenerationConfig(max_tokens=256, temperature=0.7, top_p=0.9)
+
+llm = GeminiConfig(
+    name="gemini-aistudio-flash",
+    model_id="gemini-2.5-flash",
+    auth=GeminiAIStudioAuthConfig(
+        name="gemini-aistudio-auth"
+        # Optional: if api_key is omitted, runtimes may load GEMINI_API_KEY from the environment.
+    ),
+    default_generation_parameters=generation_config,
+)
+
+llm = GeminiConfig(
+    name="gemini-vertex-flash",
+    model_id="gemini-2.0-flash-lite",
+    auth=GeminiVertexAIAuthConfig(
+        name="gemini-vertex-auth",
+        # Often still required even when ADC supplies the credentials.
+        project_id="my-gcp-project",
+        location="global",
+        # Optional: explicit credentials can be provided when ADC is not available.
+    ),
+    default_generation_parameters=generation_config,
+)
+
 from pyagentspec.llms import OllamaConfig
 
 generation_config = LlmGenerationConfig(max_tokens=512, temperature=0.9, top_p=0.9)
diff --git a/docs/pyagentspec/source/howtoguides/howto_llm_from_different_providers.rst b/docs/pyagentspec/source/howtoguides/howto_llm_from_different_providers.rst
index 18be11e9..2252d3bb 100644
--- a/docs/pyagentspec/source/howtoguides/howto_llm_from_different_providers.rst
+++ b/docs/pyagentspec/source/howtoguides/howto_llm_from_different_providers.rst
@@ -6,6 +6,7 @@ Agent Spec supports several LLM providers, each one having its own LlmConfig com
 The available LLMs are:
 
 - :ref:`OpenAiConfig <openaiconfig>`
+- :ref:`GeminiConfig <geminiconfig>`
 - :ref:`OciGenAiConfig <ocigenaiconfig>`
 - :ref:`OpenAiCompatibleConfig <openaicompatibleconfig>`
 - :ref:`VllmConfig <vllmconfig>`
@@ -183,6 +184,97 @@ You can refer to one of those models by using the ``OpenAiConfig`` Component.
 
 .. _howto-openaicompatibleconfig:
 
+GeminiConfig
+============
+
+`Gemini <https://gemini.google.com/>`_ models can be configured through ``GeminiConfig``.
+Agent Spec supports both Google AI Studio and Google Vertex AI authentication modes.
+
+Gemini authentication is modeled as a nested auth component, similar to OCI ``client_config``.
+The auth component itself remains inline during serialization. When ``api_key`` or
+``credentials`` is provided explicitly, only that sensitive field is externalized and must
+be supplied through ``components_registry`` when loading the configuration back.
+
+**Parameters**
+
+.. option:: model_id: str
+
+  Name of the model to use, for example ``gemini-2.5-flash`` or
+  ``gemini-2.0-flash-lite``.
+
+.. option:: auth: GeminiAuthConfig
+
+  Required authentication component for Gemini. As with other Agent Spec components,
+  auth configs need a ``name``. Use ``GeminiAIStudioAuthConfig(name="gemini-aistudio-auth")``
+  if you want runtimes to load ``GEMINI_API_KEY`` from the environment, or
+  ``GeminiVertexAIAuthConfig(name="gemini-vertex-auth", ...)`` for Vertex AI.
+  The auth component remains inline when serialized. If ``api_key`` or ``credentials``
+  is set explicitly, only that sensitive field is serialized as a reference.
+
+.. option:: default_generation_parameters: dict, null
+
+  Default parameters for text generation with this model.
+
+Google AI Studio authentication
+-------------------------------
+
+Use ``GeminiAIStudioAuthConfig`` when connecting through Google AI Studio.
+
+**Parameters**
+
+.. option:: api_key: str, null
+
+  Optional Gemini API key. If omitted, runtimes may load it from ``GEMINI_API_KEY``.
+  If provided explicitly, only the ``api_key`` field is externalized during
+  serialization and must be supplied separately when deserializing.
+
+**Example**
+
+.. literalinclude:: ../code_examples/howto_llm_from_different_providers.py
+    :language: python
+    :start-after: .. gemini-aistudio-start
+    :end-before: .. gemini-aistudio-end
+
+Vertex AI authentication
+------------------------
+
+Use ``GeminiVertexAIAuthConfig`` when connecting through Google Vertex AI.
+
+**Parameters**
+
+.. option:: project_id: str, null
+
+  Optional Google Cloud project identifier.
+  In practice, you may still need to set this explicitly when ADC provides
+  credentials but does not expose a default project.
+
+.. option:: location: str
+
+  Vertex AI location or region. Defaults to ``global``.
+
+.. option:: credentials: str | dict, null
+
+  Optional local file path (``str``) to a Google Cloud JSON credential file, such as a
+  service-account key file, or an inline ``dict`` containing the parsed JSON contents of
+  that file.
+  When omitted, runtimes may rely on Google Application Default Credentials (ADC), such as
+  ``GOOGLE_APPLICATION_CREDENTIALS``, credentials made available through the local
+  Google Cloud environment, or an attached service account.
+  See `Google Cloud authentication docs <https://cloud.google.com/docs/authentication/application-default-credentials>`_
+  for details.
+  This does not guarantee that ``project_id`` can also be inferred automatically.
+  If provided explicitly, only the ``credentials`` field is externalized during
+  serialization. Non-secret auth settings such as ``project_id`` and ``location``
+  remain inline in the main config.
+
+**Example**
+
+.. literalinclude:: ../code_examples/howto_llm_from_different_providers.py
+    :language: python
+    :start-after: .. gemini-vertex-start
+    :end-before: .. gemini-vertex-end
+
+
 OpenAiCompatibleConfig
 ======================
 
diff --git a/pyagentspec/src/pyagentspec/_component_registry.py b/pyagentspec/src/pyagentspec/_component_registry.py
index 82edffcb..be871a30 100644
--- a/pyagentspec/src/pyagentspec/_component_registry.py
+++ b/pyagentspec/src/pyagentspec/_component_registry.py
@@ -44,12 +44,18 @@
     ToolNode,
 )
 from pyagentspec.llms import (
+    GeminiConfig,
     OciGenAiConfig,
     OllamaConfig,
     OpenAiCompatibleConfig,
     OpenAiConfig,
     VllmConfig,
 )
+from pyagentspec.llms.geminiauthconfig import (
+    GeminiAIStudioAuthConfig,
+    GeminiAuthConfig,
+    GeminiVertexAIAuthConfig,
+)
 from pyagentspec.llms.llmconfig import LlmConfig
 from pyagentspec.llms.ociclientconfig import (
     OciClientConfig,
@@ -117,6 +123,10 @@
     "OciClientConfigWithInstancePrincipal": OciClientConfigWithInstancePrincipal,
     "OciClientConfigWithResourcePrincipal": OciClientConfigWithResourcePrincipal,
     "OciClientConfigWithSecurityToken": OciClientConfigWithSecurityToken,
+    "GeminiAuthConfig": GeminiAuthConfig,
+    "GeminiAIStudioAuthConfig": GeminiAIStudioAuthConfig,
+    "GeminiVertexAIAuthConfig": GeminiVertexAIAuthConfig,
+    "GeminiConfig": GeminiConfig,
     "OciGenAiConfig": OciGenAiConfig,
     "OllamaConfig": OllamaConfig,
     "OpenAiCompatibleConfig": OpenAiCompatibleConfig,
diff --git a/pyagentspec/src/pyagentspec/llms/__init__.py b/pyagentspec/src/pyagentspec/llms/__init__.py
index 4f5469eb..c7170151 100644
--- a/pyagentspec/src/pyagentspec/llms/__init__.py
+++ b/pyagentspec/src/pyagentspec/llms/__init__.py
@@ -4,8 +4,9 @@
 # (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0) or Universal Permissive License
 # (UPL) 1.0 (LICENSE-UPL or https://oss.oracle.com/licenses/upl), at your option.
 
-"""Define LLM configurations abstraction and concrete classes for connecting to vLLM or OCI."""
+"""Define LLM configuration abstractions and provider-specific implementations."""
 
+from .geminiconfig import GeminiConfig
 from .llmconfig import LlmConfig
 from .llmgenerationconfig import LlmGenerationConfig
 from .ocigenaiconfig import OciGenAiConfig
@@ -17,6 +18,7 @@
 __all__ = [
     "LlmConfig",
     "LlmGenerationConfig",
+    "GeminiConfig",
     "VllmConfig",
     "OciGenAiConfig",
     "OllamaConfig",
diff --git a/pyagentspec/src/pyagentspec/llms/geminiauthconfig.py b/pyagentspec/src/pyagentspec/llms/geminiauthconfig.py
new file mode 100644
index 00000000..5290a1a5
--- /dev/null
+++ b/pyagentspec/src/pyagentspec/llms/geminiauthconfig.py
@@ -0,0 +1,58 @@
+# Copyright © 2026 Oracle and/or its affiliates.
+#
+# This software is under the Apache License 2.0
+# (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0) or Universal Permissive License
+# (UPL) 1.0 (LICENSE-UPL or https://oss.oracle.com/licenses/upl), at your option.
+
+"""Defines the classes for configuring Gemini authentication."""
+
+from typing import Any, Dict, Optional
+
+from pydantic import Field
+from pydantic.json_schema import SkipJsonSchema
+
+from pyagentspec.component import Component
+from pyagentspec.sensitive_field import SensitiveField
+from pyagentspec.versioning import AgentSpecVersionEnum
+
+
+class GeminiAuthConfig(Component, abstract=True):
+    """Base class for Gemini authentication configuration."""
+
+    min_agentspec_version: SkipJsonSchema[AgentSpecVersionEnum] = Field(
+        default=AgentSpecVersionEnum.v26_2_0,
+        init=False,
+        exclude=True,
+    )
+
+
+class GeminiAIStudioAuthConfig(GeminiAuthConfig):
+    """Authentication settings for Gemini via Google AI Studio."""
+
+    api_key: SensitiveField[Optional[str]] = None
+    """API key to use. If unset, runtimes may load it from ``GEMINI_API_KEY``."""
+
+
+class GeminiVertexAIAuthConfig(GeminiAuthConfig):
+    """Authentication settings for Gemini via Google Vertex AI."""
+
+    project_id: Optional[str] = None
+    """Optional Google Cloud project identifier.
+
+    This may still need to be set explicitly when the runtime cannot infer the
+    project from Application Default Credentials (ADC) or other local Google
+    Cloud configuration.
+    """
+    location: str = "global"
+    """Vertex AI location/region."""
+    credentials: SensitiveField[Optional[str | Dict[str, Any]]] = None
+    """Optional local file path to a Google Cloud JSON credential file, such as a
+    service-account key file, or an inline dictionary containing the parsed JSON
+    contents of that file.
+
+    When unset, runtimes may rely on Application Default Credentials (ADC), such as
+    ``GOOGLE_APPLICATION_CREDENTIALS``, credentials made available through the local
+    Google Cloud environment, or an attached service account.
+    Even then, ``project_id`` may still need to be provided separately if it
+    cannot be resolved from the environment.
+    """
diff --git a/pyagentspec/src/pyagentspec/llms/geminiconfig.py b/pyagentspec/src/pyagentspec/llms/geminiconfig.py
new file mode 100644
index 00000000..4c3dc36c
--- /dev/null
+++ b/pyagentspec/src/pyagentspec/llms/geminiconfig.py
@@ -0,0 +1,29 @@
+# Copyright © 2026 Oracle and/or its affiliates.
+#
+# This software is under the Apache License 2.0
+# (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0) or Universal Permissive License
+# (UPL) 1.0 (LICENSE-UPL or https://oss.oracle.com/licenses/upl), at your option.
+
+"""Defines the class for configuring how to connect to Gemini LLMs."""
+
+from pydantic import Field, SerializeAsAny
+from pydantic.json_schema import SkipJsonSchema
+
+from pyagentspec.llms.geminiauthconfig import GeminiAuthConfig
+from pyagentspec.llms.llmconfig import LlmConfig
+from pyagentspec.versioning import AgentSpecVersionEnum
+
+
+class GeminiConfig(LlmConfig):
+    """Configure a connection to a Gemini LLM (AI Studio or Vertex AI)."""
+
+    min_agentspec_version: SkipJsonSchema[AgentSpecVersionEnum] = Field(
+        default=AgentSpecVersionEnum.v26_2_0,
+        init=False,
+        exclude=True,
+    )
+
+    model_id: str
+    """Identifier of the Gemini model to use."""
+    auth: SerializeAsAny[GeminiAuthConfig]
+    """Authentication configuration used to connect to the Gemini service."""
diff --git a/pyagentspec/tests/adapters/langgraph/llms/test_ocigenai_conversion.py b/pyagentspec/tests/adapters/langgraph/llms/test_ocigenai_conversion.py
index 296af353..0bdf4f51 100644
--- a/pyagentspec/tests/adapters/langgraph/llms/test_ocigenai_conversion.py
+++ b/pyagentspec/tests/adapters/langgraph/llms/test_ocigenai_conversion.py
@@ -70,11 +70,12 @@ def auth_profile_contains_security_token(client_config):
 
 
 # Evaluate once at import-time for skip decorator
+_SEC_TOKEN_PROFILE_NAME = OCI_AUTH_PROFILE_WITH_SECURITY_TOKEN or "DEFAULT"
 _SEC_TOKEN_PRESENT = auth_profile_contains_security_token(
     OciClientConfigWithSecurityToken(
         name="with_security_token",
         service_endpoint=OCI_SERVICE_ENDPOINT,
-        auth_profile=OCI_AUTH_PROFILE_WITH_SECURITY_TOKEN or "DEFAULT",
+        auth_profile=_SEC_TOKEN_PROFILE_NAME,
         auth_file_location=_oci_user_config_path(),
     )
 )
@@ -121,7 +122,7 @@ def test_ocigenai_llm_conversion_security_token(default_generation_parameters):
     client_config = OciClientConfigWithSecurityToken(
         name="with_security_token",
         service_endpoint=OCI_SERVICE_ENDPOINT,
-        auth_profile="WEBAUTH",
+        auth_profile=_SEC_TOKEN_PROFILE_NAME,
         auth_file_location=_oci_user_config_path(),
     )
     llm_cfg = OciGenAiConfig(
diff --git a/pyagentspec/tests/serialization/test_gemini_config.py b/pyagentspec/tests/serialization/test_gemini_config.py
new file mode 100644
index 00000000..6f90926d
--- /dev/null
+++ b/pyagentspec/tests/serialization/test_gemini_config.py
@@ -0,0 +1,317 @@
+# Copyright © 2026 Oracle and/or its affiliates.
+#
+# This software is under the Apache License 2.0
+# (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0) or Universal Permissive License
+# (UPL) 1.0 (LICENSE-UPL or https://oss.oracle.com/licenses/upl), at your option.
+
+import json
+from typing import Any
+
+import pytest
+from pydantic import ValidationError
+
+from pyagentspec.llms import GeminiConfig
+from pyagentspec.llms.geminiauthconfig import GeminiAIStudioAuthConfig, GeminiVertexAIAuthConfig
+from pyagentspec.serialization import AgentSpecDeserializer, AgentSpecSerializer
+from pyagentspec.versioning import AgentSpecVersionEnum
+
+GEMINI_CONFIG_ID = "gemini-config-id"
+GEMINI_CONFIG_NAME = "gemini"
+GEMINI_AISTUDIO_AUTH_ID = "gemini-aistudio-auth-id"
+GEMINI_AISTUDIO_AUTH_NAME = "gemini-aistudio-auth"
+GEMINI_VERTEX_AUTH_ID = "gemini-vertex-auth-id"
+GEMINI_VERTEX_AUTH_NAME = "gemini-vertex-auth"
+
+
+def _assert_serialized_geminiconfig_fields(
+    serialized_llm_as_dict: dict[str, Any], *, model_id: str
+) -> None:
+    assert serialized_llm_as_dict["component_type"] == "GeminiConfig"
+    assert serialized_llm_as_dict["id"] == GEMINI_CONFIG_ID
+    assert serialized_llm_as_dict["name"] == GEMINI_CONFIG_NAME
+    assert serialized_llm_as_dict["description"] is None
+    assert serialized_llm_as_dict["metadata"] == {}
+    assert serialized_llm_as_dict["default_generation_parameters"] is None
+    assert serialized_llm_as_dict["model_id"] == model_id
+    assert serialized_llm_as_dict["agentspec_version"] == AgentSpecVersionEnum.v26_2_0.value
+
+
+@pytest.mark.parametrize(
+    ("auth", "model_id", "expected_auth", "expected_auth_type"),
+    [
+        (
+            GeminiAIStudioAuthConfig(
+                id=GEMINI_AISTUDIO_AUTH_ID,
+                name=GEMINI_AISTUDIO_AUTH_NAME,
+            ),
+            "gemini-2.5-flash",
+            {
+                "component_type": "GeminiAIStudioAuthConfig",
+                "id": GEMINI_AISTUDIO_AUTH_ID,
+                "name": GEMINI_AISTUDIO_AUTH_NAME,
+                "description": None,
+                "metadata": {},
+                "api_key": None,
+            },
+            GeminiAIStudioAuthConfig,
+        ),
+        (
+            GeminiVertexAIAuthConfig(
+                id=GEMINI_VERTEX_AUTH_ID,
+                name=GEMINI_VERTEX_AUTH_NAME,
+            ),
+            "gemini-2.0-flash-lite",
+            {
+                "component_type": "GeminiVertexAIAuthConfig",
+                "id": GEMINI_VERTEX_AUTH_ID,
+                "name": GEMINI_VERTEX_AUTH_NAME,
+                "description": None,
+                "metadata": {},
+                "project_id": None,
+                "location": "global",
+                "credentials": None,
+            },
+            GeminiVertexAIAuthConfig,
+        ),
+        (
+            GeminiVertexAIAuthConfig(
+                id=GEMINI_VERTEX_AUTH_ID,
+                name=GEMINI_VERTEX_AUTH_NAME,
+                project_id="project-id",
+                location="us-central1",
+            ),
+            "gemini-2.0-flash-lite",
+            {
+                "component_type": "GeminiVertexAIAuthConfig",
+                "id": GEMINI_VERTEX_AUTH_ID,
+                "name": GEMINI_VERTEX_AUTH_NAME,
+                "description": None,
+                "metadata": {},
+                "project_id": "project-id",
+                "location": "us-central1",
+                "credentials": None,
+            },
+            GeminiVertexAIAuthConfig,
+        ),
+    ],
+    ids=["aistudio-empty", "vertex-empty", "vertex-without-credentials"],
+)
+def test_can_serialize_and_deserialize_gemini_config_with_inline_auth(
+    auth: GeminiAIStudioAuthConfig | GeminiVertexAIAuthConfig,
+    model_id: str,
+    expected_auth: dict[str, Any],
+    expected_auth_type: type[object],
+) -> None:
+    llm_config = GeminiConfig(
+        id=GEMINI_CONFIG_ID,
+        name=GEMINI_CONFIG_NAME,
+        model_id=model_id,
+        auth=auth,
+    )
+
+    serialized_llm = AgentSpecSerializer().to_json(llm_config)
+    serialized_llm_as_dict = json.loads(serialized_llm)
+
+    assert '"$component_ref"' not in serialized_llm
+    _assert_serialized_geminiconfig_fields(serialized_llm_as_dict, model_id=model_id)
+    assert serialized_llm_as_dict["auth"] == expected_auth
+
+    deserialized_llm = AgentSpecDeserializer().from_json(serialized_llm)
+
+    assert deserialized_llm == llm_config
+    assert deserialized_llm.min_agentspec_version == AgentSpecVersionEnum.v26_2_0
+    assert isinstance(deserialized_llm.auth, expected_auth_type)
+
+
+@pytest.mark.parametrize(
+    (
+        "auth",
+        "model_id",
+        "expected_auth",
+        "components_registry",
+        "missing_component_ref",
+        "hidden_values",
+        "expected_auth_type",
+    ),
+    [
+        (
+            GeminiAIStudioAuthConfig(
+                id=GEMINI_AISTUDIO_AUTH_ID,
+                name=GEMINI_AISTUDIO_AUTH_NAME,
+                api_key="THIS_IS_SECRET",
+            ),
+            "gemini-2.5-flash",
+            {
+                "component_type": "GeminiAIStudioAuthConfig",
+                "id": GEMINI_AISTUDIO_AUTH_ID,
+                "name": GEMINI_AISTUDIO_AUTH_NAME,
+                "description": None,
+                "metadata": {},
+                "api_key": {"$component_ref": f"{GEMINI_AISTUDIO_AUTH_ID}.api_key"},
+            },
+            {f"{GEMINI_AISTUDIO_AUTH_ID}.api_key": "THIS_IS_SECRET"},
+            rf"{GEMINI_AISTUDIO_AUTH_ID}\.api_key",
+            ("THIS_IS_SECRET",),
+            GeminiAIStudioAuthConfig,
+        ),
+        (
+            GeminiVertexAIAuthConfig(
+                id=GEMINI_VERTEX_AUTH_ID,
+                name=GEMINI_VERTEX_AUTH_NAME,
+                project_id="project-id",
+                location="global",
+                credentials={
+                    "type": "service_account",
+                    "client_email": "agent@example.com",
+                    "private_key": "line1\\nline2",
+                },
+            ),
+            "gemini-2.0-flash-lite",
+            {
+                "component_type": "GeminiVertexAIAuthConfig",
+                "id": GEMINI_VERTEX_AUTH_ID,
+                "name": GEMINI_VERTEX_AUTH_NAME,
+                "description": None,
+                "metadata": {},
+                "project_id": "project-id",
+                "location": "global",
+                "credentials": {"$component_ref": f"{GEMINI_VERTEX_AUTH_ID}.credentials"},
+            },
+            {
+                f"{GEMINI_VERTEX_AUTH_ID}.credentials": {
+                    "type": "service_account",
+                    "client_email": "agent@example.com",
+                    "private_key": "line1\\nline2",
+                },
+            },
+            rf"{GEMINI_VERTEX_AUTH_ID}\.credentials",
+            ("service_account", "agent@example.com"),
+            GeminiVertexAIAuthConfig,
+        ),
+    ],
+    ids=["aistudio-api-key", "vertex-credentials"],
+)
+def test_can_serialize_and_deserialize_gemini_config_with_sensitive_auth_fields(
+    auth: GeminiAIStudioAuthConfig | GeminiVertexAIAuthConfig,
+    model_id: str,
+    expected_auth: dict[str, Any],
+    components_registry: dict[str, Any],
+    missing_component_ref: str,
+    hidden_values: tuple[str, ...],
+    expected_auth_type: type[object],
+) -> None:
+    llm_config = GeminiConfig(
+        id=GEMINI_CONFIG_ID,
+        name=GEMINI_CONFIG_NAME,
+        model_id=model_id,
+        auth=auth,
+    )
+
+    serialized_llm = AgentSpecSerializer().to_json(llm_config)
+    serialized_llm_as_dict = json.loads(serialized_llm)
+
+    for hidden_value in hidden_values:
+        assert hidden_value not in serialized_llm
+
+    _assert_serialized_geminiconfig_fields(serialized_llm_as_dict, model_id=model_id)
+    assert serialized_llm_as_dict["auth"] == expected_auth
+
+    with pytest.raises(ValueError, match=missing_component_ref):
+        AgentSpecDeserializer().from_json(serialized_llm)
+
+    deserialized_llm = AgentSpecDeserializer().from_json(
+        serialized_llm,
+        components_registry=components_registry,
+    )
+
+    assert deserialized_llm == llm_config
+    assert isinstance(deserialized_llm.auth, expected_auth_type)
+
+
+def test_geminiconfig_requires_auth() -> None:
+    with pytest.raises(ValidationError, match="auth"):
+        GeminiConfig(name=GEMINI_CONFIG_NAME, model_id="gemini-2.5-flash")
+
+
+def test_can_deserialize_gemini_config_with_inline_vertex_auth_component() -> None:
+    serialized_llm = json.dumps(
+        {
+            "component_type": "GeminiConfig",
+            "id": GEMINI_CONFIG_ID,
+            "name": GEMINI_CONFIG_NAME,
+            "model_id": "gemini-2.0-flash-lite",
+            "auth": {
+                "component_type": "GeminiVertexAIAuthConfig",
+                "id": GEMINI_VERTEX_AUTH_ID,
+                "name": GEMINI_VERTEX_AUTH_NAME,
+            },
+            "agentspec_version": AgentSpecVersionEnum.v26_2_0.value,
+        }
+    )
+
+    deserialized_llm = AgentSpecDeserializer().from_json(serialized_llm)
+
+    assert isinstance(deserialized_llm, GeminiConfig)
+    assert isinstance(deserialized_llm.auth, GeminiVertexAIAuthConfig)
+    assert deserialized_llm.auth == GeminiVertexAIAuthConfig(
+        id=GEMINI_VERTEX_AUTH_ID,
+        name=GEMINI_VERTEX_AUTH_NAME,
+    )
+
+
+def test_deserializing_gemini_config_without_auth_raises_error() -> None:
+    serialized_llm = json.dumps(
+        {
+            "component_type": "GeminiConfig",
+            "id": GEMINI_CONFIG_ID,
+            "name": GEMINI_CONFIG_NAME,
+            "model_id": "gemini-2.0-flash-lite",
+            "agentspec_version": AgentSpecVersionEnum.v26_2_0.value,
+        }
+    )
+
+    with pytest.raises(ValidationError, match="auth"):
+        AgentSpecDeserializer().from_json(serialized_llm)
+
+
+@pytest.mark.parametrize(
+    "model_id",
+    [
+        "gemini/gemini-2.5-flash",
+        "vertex_ai/gemini-2.0-flash-lite",
+    ],
+)
+def test_gemini_config_preserves_prefixed_model_id(model_id: str) -> None:
+    llm_config = GeminiConfig(
+        id=GEMINI_CONFIG_ID,
+        name=GEMINI_CONFIG_NAME,
+        model_id=model_id,
+        auth=GeminiAIStudioAuthConfig(
+            id=GEMINI_AISTUDIO_AUTH_ID,
+            name=GEMINI_AISTUDIO_AUTH_NAME,
+        ),
+    )
+
+    serialized_llm = AgentSpecSerializer().to_json(llm_config)
+    serialized_llm_as_dict = json.loads(serialized_llm)
+    _assert_serialized_geminiconfig_fields(serialized_llm_as_dict, model_id=model_id)
+    assert serialized_llm_as_dict["auth"]["component_type"] == "GeminiAIStudioAuthConfig"
+
+    deserialized_llm = AgentSpecDeserializer().from_json(serialized_llm)
+
+    assert llm_config.model_id == model_id
+    assert deserialized_llm.model_id == model_id
+
+
+def test_serializing_gemini_config_with_unsupported_version_raises_error() -> None:
+    llm_config = GeminiConfig(
+        name=GEMINI_CONFIG_NAME,
+        model_id="gemini-2.5-flash",
+        auth=GeminiAIStudioAuthConfig(name=GEMINI_AISTUDIO_AUTH_NAME),
+    )
+
+    with pytest.raises(ValueError, match="Invalid agentspec_version"):
+        AgentSpecSerializer().to_dict(
+            llm_config,
+            agentspec_version=AgentSpecVersionEnum.v26_1_0,
+        )