diff --git a/bin/describe/aliases_targets.ml b/bin/describe/aliases_targets.ml
index 976c0f4a77e..3bf075c5469 100644
--- a/bin/describe/aliases_targets.ml
+++ b/bin/describe/aliases_targets.ml
@@ -1,13 +1,13 @@
 open Import
 
-let ls_term (fetch_results : Path.Build.t -> string list Action_builder.t) =
+let ls_term_gen extra_args fetch_results =
   let+ builder = Common.Builder.term
   (* CR-someday Alizter: document this option *)
   and+ paths = Arg.(value & pos_all string [ "." ] & info [] ~docv:"DIR" ~doc:None)
   and+ context =
     Common.context_arg
       ~doc:(Some "The context to look in. Defaults to the default context.")
-  in
+  and+ extra = extra_args in
   let common, config = Common.init builder in
   let request (_ : Dune_rules.Main.build_system) =
     let header = List.length paths > 1 in
@@ -49,33 +49,47 @@ let ls_term (fetch_results : Path.Build.t -> string list Action_builder.t) =
                   (Path.to_string_maybe_quoted dir)
               ]
         in
-        (* Check if the directory exists. *)
+        (* Check if the directory exists (in source tree, as a directory target,
+           or as a build-only directory). *)
         let* () =
           Action_builder.of_memo
           @@
           let open Memo.O in
-          Source_tree.find_dir src_dir
+          Load_rules.load_dir ~dir:(Path.build build_dir)
           >>= function
-          | Some _ -> Memo.return ()
-          | None ->
-            (* The directory didn't exist. We therefore check if it was a
-               directory target and error for the user accordingly. *)
-            let+ is_dir_target =
-              Load_rules.is_under_directory_target (Path.build build_dir)
-            in
-            if is_dir_target
-            then
-              User_error.raise
-                [ Pp.textf
-                    "Directory %s is a directory target. This command does not support \
-                     the inspection of directory targets."
-                    (Path.to_string dir)
-                ]
-            else
-              User_error.raise
-                [ Pp.textf "Directory %s does not exist." (Path.to_string dir) ]
+          | Load_rules.Loaded.Build_under_directory_target _ ->
+            (* Directory target - allow it through for inspection *)
+            Memo.return ()
+          | External _ | Build _ | Source _ ->
+            (* Check if directory exists in source tree or is a valid build-only directory *)
+            Source_tree.find_dir src_dir
+            >>= (function
+             | Some _ -> Memo.return () (* Exists in source tree *)
+             | None ->
+               (* Not in source tree, check if it's a valid build-only subdirectory *)
+               (match Path.Build.parent build_dir with
+                | None ->
+                  (* Build context root always exists *)
+                  Memo.return ()
+                | Some parent_dir ->
+                  Load_rules.load_dir ~dir:(Path.build parent_dir)
+                  >>| (function
+                   | Load_rules.Loaded.Build { allowed_subdirs; _ } ->
+                     let subdir_set =
+                       Dune_engine.Dir_set.descend
+                         allowed_subdirs
+                         (Path.Build.basename build_dir)
+                     in
+                     if Dune_engine.Dir_set.here subdir_set
+                     then ()
+                     else
+                       User_error.raise
+                         [ Pp.textf "Directory %s does not exist." (Path.to_string dir) ]
+                   | _ ->
+                     User_error.raise
+                       [ Pp.textf "Directory %s does not exist." (Path.to_string dir) ])))
         in
-        let+ targets = fetch_results build_dir in
+        let+ targets = fetch_results extra build_dir in
         (* If we are printing multiple directories, we print the directory
            name as a header. *)
         (if header then [ Pp.textf "%s:" (Path.to_string dir) ] else [])
@@ -92,7 +106,7 @@ let ls_term (fetch_results : Path.Build.t -> string list Action_builder.t) =
 ;;
 
 module Aliases_cmd = struct
-  let fetch_results (dir : Path.Build.t) =
+  let fetch_results () (dir : Path.Build.t) =
     let open Action_builder.O in
     let+ alias_targets =
       let+ load_dir =
@@ -105,7 +119,7 @@ module Aliases_cmd = struct
     List.map ~f:Dune_engine.Alias.Name.to_string alias_targets
   ;;
 
-  let term = ls_term fetch_results
+  let term = ls_term_gen (Term.const ()) fetch_results
 
   let command =
     let doc = "Print aliases in a given directory. Works similarly to ls." in
@@ -114,28 +128,52 @@ module Aliases_cmd = struct
 end
 
 module Targets_cmd = struct
-  let fetch_results (dir : Path.Build.t) =
+  let fetch_results all (dir : Path.Build.t) =
     let open Action_builder.O in
-    let+ targets =
-      let open Memo.O in
-      Target.all_direct_targets (Some (Path.Build.drop_build_context_exn dir))
-      >>| Path.Build.Map.to_list
-      |> Action_builder.of_memo
+    let* targets =
+      Action_builder.of_memo (Build_system.targets_of ~dir:(Path.build dir))
+    in
+    let+ subdirs =
+      Action_builder.of_memo
+        (let open Memo.O in
+         Load_rules.load_dir ~dir:(Path.build dir)
+         >>| function
+         | Load_rules.Loaded.Build { allowed_subdirs; _ } ->
+           (match Dune_engine.Dir_set.toplevel_subdirs allowed_subdirs with
+            | Infinite -> []
+            | Finite set ->
+              Filename.Set.to_list set
+              |> Filename.L.to_string
+              |> List.filter ~f:(fun name ->
+                all || String.length name = 0 || name.[0] <> '.')
+              |> List.map ~f:(fun name -> name ^ Filename.dir_sep))
+         | _ -> [])
     in
-    List.filter_map targets ~f:(fun (path, kind) ->
-      match Path.Build.equal (Path.Build.parent_exn path) dir with
-      | false -> None
-      | true ->
-        (* directory targets can be distinguied by the trailing path separator
-        *)
-        Some
-          (match kind with
-           | Target.File -> Path.Build.basename path |> Filename.to_string
-           | Directory ->
-             (Path.Build.basename path |> Filename.to_string) ^ Filename.dir_sep))
+    let target_names =
+      match Dune_targets.validate targets with
+      | Valid validated ->
+        Dune_targets.Validated.fold
+          validated
+          ~init:[]
+          ~file:(fun p acc -> (Path.Build.basename p |> Filename.to_string) :: acc)
+          ~dir:(fun p acc ->
+            ((Path.Build.basename p |> Filename.to_string) ^ Filename.dir_sep) :: acc)
+      | No_targets -> []
+      | Inconsistent_parent_dir | File_and_directory_target_with_the_same_name _ -> []
+    in
+    List.sort ~compare:String.compare (target_names @ subdirs)
+  ;;
+
+  let extra_args =
+    Arg.(
+      value
+      & flag
+      & info
+          [ "a"; "all" ]
+          ~doc:(Some "Show hidden directories (those starting with '.')."))
   ;;
 
-  let term = ls_term fetch_results
+  let term = ls_term_gen extra_args fetch_results
 
   let command =
     let doc = "Print targets in a given directory. Works similarly to ls." in
diff --git a/doc/changes/changed/14665.md b/doc/changes/changed/14665.md
new file mode 100644
index 00000000000..52ba9cb042e
--- /dev/null
+++ b/doc/changes/changed/14665.md
@@ -0,0 +1,3 @@
+- `dune show targets` now includes subdirectories that contain build targets,
+  and accepts an `-a`/`--all` flag to also include hidden directories (those
+  starting with `.`). (#14665, fixes #13783, @Alizter)
diff --git a/doc/changes/changed/14666.md b/doc/changes/changed/14666.md
new file mode 100644
index 00000000000..24ffd0142fe
--- /dev/null
+++ b/doc/changes/changed/14666.md
@@ -0,0 +1,2 @@
+- `dune show targets` now looks inside directory targets, so users can inspect
+  the files produced under a directory target. (#14666, fixes #13780, @Alizter)
diff --git a/doc/changes/fixed/14664.md b/doc/changes/fixed/14664.md
new file mode 100644
index 00000000000..c4f66283751
--- /dev/null
+++ b/doc/changes/fixed/14664.md
@@ -0,0 +1,2 @@
+- `dune show targets` now accepts build-only directories such as
+  `_build/default/.simple.objs`. (#14664, fixes #13782, @Alizter)
diff --git a/doc/reference/cli.rst b/doc/reference/cli.rst
index 3e9aca7f7f7..b298a58edd8 100644
--- a/doc/reference/cli.rst
+++ b/doc/reference/cli.rst
@@ -71,7 +71,12 @@ documentation for each command is available through ``dune COMMAND --help``.
 
    .. describe:: dune describe targets
 
-      Print targets in a given directory. Works similarly to ls.
+      Print targets in a given directory. Works similarly to ls. The directory
+      may be a path in the source tree, a build-only directory under
+      ``_build/`` (such as ``_build/default/.lib.objs``), or a directory
+      target (including subdirectories of one). Subdirectories containing
+      build targets are listed alongside the targets themselves; pass
+      ``-a``/``--all`` to also include hidden directories.
 
    .. describe:: dune describe workspace
 
diff --git a/src/dune_engine/build_system.ml b/src/dune_engine/build_system.ml
index 3edbadd92fa..50b35f07abe 100644
--- a/src/dune_engine/build_system.ml
+++ b/src/dune_engine/build_system.ml
@@ -1062,6 +1062,57 @@ let files_of ~dir =
     Filename_set.create ~dir filenames
 ;;
 
+let targets_of ~dir =
+  Load_rules.load_dir ~dir
+  >>= function
+  | Source _ | External _ ->
+    (* Source/external dirs have no build targets *)
+    Memo.return Targets.empty
+  | Build { rules_here; _ } ->
+    let files =
+      Path.Build.Map.keys rules_here.by_file_targets |> Path.Build.Set.of_list
+    in
+    let dirs =
+      Path.Build.Map.keys rules_here.by_directory_targets |> Path.Build.Set.of_list
+    in
+    Memo.return (Targets.create ~files ~dirs)
+  | Build_under_directory_target { directory_target_ancestor } ->
+    let+ produced = build_dir (Path.build directory_target_ancestor) in
+    let build_dir_path = Path.as_in_build_dir_exn dir in
+    (* Navigate to the requested directory within the produced targets *)
+    let rec find_dir_contents (contents : _ Targets.Produced.dir_contents) path =
+      match path with
+      | [] -> Some contents
+      | component :: rest ->
+        (match Filename.Map.find contents.subdirs component with
+         | Some sub -> find_dir_contents sub rest
+         | None -> None)
+    in
+    let path_within =
+      match
+        Path.Local.descendant
+          (Path.Build.local build_dir_path)
+          ~of_:(Path.Build.local produced.root)
+      with
+      | Some p -> Path.Local.explode p
+      | None -> []
+    in
+    (match find_dir_contents produced.contents path_within with
+     | Some contents ->
+       let files =
+         Filename.Map.keys contents.files
+         |> List.map ~f:(Path.Build.relative_fname build_dir_path)
+         |> Path.Build.Set.of_list
+       in
+       let dirs =
+         Filename.Map.keys contents.subdirs
+         |> List.map ~f:(Path.Build.relative_fname build_dir_path)
+         |> Path.Build.Set.of_list
+       in
+       Targets.create ~files ~dirs
+     | None -> Targets.empty)
+;;
+
 let caused_by_cancellation (exn : Exn_with_backtrace.t) =
   match exn.exn with
   | Scheduler.Run.Build_cancelled -> true
diff --git a/src/dune_engine/build_system.mli b/src/dune_engine/build_system.mli
index aadf2ee8437..d120b1c16f8 100644
--- a/src/dune_engine/build_system.mli
+++ b/src/dune_engine/build_system.mli
@@ -35,6 +35,10 @@ val eval_pred : File_selector.t -> Filename_set.t Memo.t
 (** Same as [eval_pred] with [Predicate.true_] as predicate. *)
 val files_of : dir:Path.t -> Filename_set.t Memo.t
 
+(** Return all targets (files and directories) in a directory.
+    Handles directory targets by building them first. *)
+val targets_of : dir:Path.t -> Targets.t Memo.t
+
 (** Execute an action. The execution is cached. *)
 val execute_action : observing_facts:Dep.Facts.t -> Rule.Anonymous_action.t -> unit Memo.t
 
diff --git a/test/blackbox-tests/test-cases/describe/targets.t/dune b/test/blackbox-tests/test-cases/describe/targets.t/dune
index b848d9cd25e..3d2aa22c2e8 100644
--- a/test/blackbox-tests/test-cases/describe/targets.t/dune
+++ b/test/blackbox-tests/test-cases/describe/targets.t/dune
@@ -5,5 +5,5 @@
  (targets (dir d))
  (action
   (progn
-   (run mkdir d)
-   (run cat > d/foo))))
+   (run mkdir -p d/subdir)
+   (run touch d/foo d/bar d/subdir/nested))))
diff --git a/test/blackbox-tests/test-cases/describe/targets.t/run.t b/test/blackbox-tests/test-cases/describe/targets.t/run.t
index e7f701a39fd..392cc9a01ab 100644
--- a/test/blackbox-tests/test-cases/describe/targets.t/run.t
+++ b/test/blackbox-tests/test-cases/describe/targets.t/run.t
@@ -8,7 +8,10 @@ With no directory provided to the command, it should default to the current
 working directory.
 
   $ dune show targets
+  _doc/
+  _doc_new/
   a.ml
+  b/
   d/
   dune
   dune-project
@@ -23,7 +26,10 @@ used, and only the targets available in that directory will be displayed.
 
   $ dune show targets . b/
   .:
+  _doc/
+  _doc_new/
   a.ml
+  b/
   d/
   dune
   dune-project
@@ -45,7 +51,10 @@ used, and only the targets available in that directory will be displayed.
 The command also works with files in the _build directory.
 
   $ dune show targets _build/default/
+  _doc/
+  _doc_new/
   a.ml
+  b/
   d/
   dune
   dune-project
@@ -64,21 +73,54 @@ The command also works with files in the _build directory.
   simple2.cmxs
   simple2.ml-gen
 
-We cannot see inside directory targets
+We can see inside directory targets. The directory target `d` contains files
+and a subdirectory.
 
   $ dune show targets d
-  Error: Directory d is a directory target. This command does not support the
-  inspection of directory targets.
+  bar
+  foo
+  subdir/
 
-We cannot show targets in build-only directories that don't exist in the source
-tree, like .simple.objs:
+We can also inspect directory targets using the _build path:
+
+  $ dune show targets _build/default/d
+  bar
+  foo
+  subdir/
+
+We can also look inside subdirectories of directory targets:
+
+  $ dune show targets d/subdir
+  nested
+
+  $ dune show targets _build/default/d/subdir
+  nested
+
+Build-only directories that don't exist in the source tree, like .simple.objs
+(Dune's internal object directory for the `simple` library), can now be
+queried:
 
   $ dune show targets .simple.objs
-  Error: Directory .simple.objs does not exist.
+  byte/
+  cctx.ocaml-index
+  jsoo/
+  native/
 
-CR-soon Alizter: This should work
   $ dune show targets _build/default/.simple.objs
-  Error: Directory _build/default/.simple.objs does not exist.
+  byte/
+  cctx.ocaml-index
+  jsoo/
+  native/
+
+With --all, hidden directories are also shown:
+
+  $ dune show targets --all .simple.objs
+  .bin/
+  .utop/
+  byte/
+  cctx.ocaml-index
+  jsoo/
+  native/
 
 And we error on non-existent directories