diff --git a/packages/googleai_dart/lib/src/client.dart b/packages/googleai_dart/lib/src/client.dart
index 605aec83..c6abc41a 100644
--- a/packages/googleai_dart/lib/src/client.dart
+++ b/packages/googleai_dart/lib/src/client.dart
@@ -43,6 +43,12 @@ class GoogleAIClient extends g.GoogleAIClient {
           client: client ?? createDefaultHttpClient(),
         );
 
+  /// Set or replace the API key.
+  set apiKey(final String value) => queryParams['key'] = value;
+
+  /// Get the API key.
+  String get apiKey => queryParams['key'];
+
   // ------------------------------------------
   // METHOD: streamGenerateContent
   // ------------------------------------------
diff --git a/packages/langchain_google/lib/src/chat_models/google_ai/chat_google_generative_ai.dart b/packages/langchain_google/lib/src/chat_models/google_ai/chat_google_generative_ai.dart
index 83a8d91b..ec8b5f57 100644
--- a/packages/langchain_google/lib/src/chat_models/google_ai/chat_google_generative_ai.dart
+++ b/packages/langchain_google/lib/src/chat_models/google_ai/chat_google_generative_ai.dart
@@ -167,6 +167,12 @@ class ChatGoogleGenerativeAI
   /// A UUID generator.
   late final Uuid _uuid = const Uuid();
 
+  /// Set or replace the API key.
+  set apiKey(final String value) => _client.apiKey = value;
+
+  /// Get the API key.
+  String get apiKey => _client.apiKey;
+
   @override
   String get modelType => 'chat-google-generative-ai';