diff --git a/packages/toolbox-adk/package.json b/packages/toolbox-adk/package.json
index 9cb8694..4f9fa83 100644
--- a/packages/toolbox-adk/package.json
+++ b/packages/toolbox-adk/package.json
@@ -51,6 +51,6 @@
         "@toolbox-sdk/core": "^0.1.2",
         "axios": "^1.12.2",
         "openapi-types": "^12.1.3",
-        "zod": "^3.24.4"
+        "zod": "^4.0.0"
     }
 }
diff --git a/packages/toolbox-core/package.json b/packages/toolbox-core/package.json
index fc2571a..5dc0bbb 100644
--- a/packages/toolbox-core/package.json
+++ b/packages/toolbox-core/package.json
@@ -54,6 +54,6 @@
         "google-auth-library": "^10.0.0"
     },
     "peerDependencies": {
-        "zod": "^3.24.4"
+        "zod": "^4.0.0"
     }
 }