diff --git a/lib/keycloak.d.ts b/lib/keycloak.d.ts
index 9f5e07c..c204c76 100644
--- a/lib/keycloak.d.ts
+++ b/lib/keycloak.d.ts
@@ -218,6 +218,12 @@ export interface KeycloakInitOptions {
 	 */
 	messageReceiveTimeout?: number
 
+	/**
+	 * Configures whether the adapter should include the refresh token in the JWT.
+	 * @default true
+	 */
+	refreshTokenIsJWT?: boolean
+
 	/**
 	 * When onLoad is 'login-required', sets the 'ui_locales' query param in compliance with section 3.1.2.1
 	 * of the OIDC 1.0 specification.
diff --git a/lib/keycloak.js b/lib/keycloak.js
index c59e5f7..bf19491 100755
--- a/lib/keycloak.js
+++ b/lib/keycloak.js
@@ -85,6 +85,8 @@ export default class Keycloak {
     /** @type {string=} */
     scope;
     messageReceiveTimeout = 10000;
+    /** @type {boolean=} */
+    refreshTokenIsJWT;
     /** @type {string=} */
     idToken;
     /** @type {KeycloakTokenParsed=} */
@@ -272,6 +274,12 @@ export default class Keycloak {
             this.messageReceiveTimeout = initOptions.messageReceiveTimeout;
         }
 
+        if (typeof initOptions.refreshTokenIsJWT === 'boolean') {
+            this.refreshTokenIsJWT = initOptions.refreshTokenIsJWT;
+        } else {
+            this.refreshTokenIsJWT = true;
+        }
+
         await this.#loadConfig();
         await this.#check3pCookiesSupported()
         await this.#processInit(initOptions);
@@ -1535,7 +1543,9 @@ export default class Keycloak {
 
         if (refreshToken) {
             this.refreshToken = refreshToken;
-            this.refreshTokenParsed = decodeToken(refreshToken);
+            if (this.refreshTokenIsJWT === true) {
+              this.refreshTokenParsed = decodeToken(refreshToken);
+            }
         } else {
             delete this.refreshToken;
             delete this.refreshTokenParsed;