diff --git a/packages/stream_chat/lib/src/api/channel.dart b/packages/stream_chat/lib/src/api/channel.dart
index 69d967fe..657126c1 100644
--- a/packages/stream_chat/lib/src/api/channel.dart
+++ b/packages/stream_chat/lib/src/api/channel.dart
@@ -507,9 +507,9 @@ class Channel {
 
   /// Pins provided message
   Future<UpdateMessageResponse> pinMessage(
-    Message message,
+    Message message, [
     Object? timeoutOrExpirationDate,
-  ) {
+  ]) {
     assert(() {
       if (timeoutOrExpirationDate is! DateTime &&
           timeoutOrExpirationDate != null &&
@@ -517,7 +517,7 @@ class Channel {
         throw ArgumentError('Invalid timeout or Expiration date');
       }
       return true;
-    }(), 'Check for invalid token or expiration date');
+    }(), 'Check whether time out is valid');
 
     DateTime? pinExpires;
     if (timeoutOrExpirationDate is DateTime) {
diff --git a/packages/stream_chat/lib/src/client.dart b/packages/stream_chat/lib/src/client.dart
index 05f2559b..6e7caa9e 100644
--- a/packages/stream_chat/lib/src/client.dart
+++ b/packages/stream_chat/lib/src/client.dart
@@ -1361,12 +1361,13 @@ class StreamChatClient {
   /// [timeoutOrExpirationDate] can either be a [DateTime] or a value in seconds
   /// to be added to [DateTime.now]
   Future<UpdateMessageResponse> pinMessage(
-    Message message,
-    Object timeoutOrExpirationDate,
-  ) {
+    Message message, [
+    Object? timeoutOrExpirationDate,
+  ]) {
     assert(() {
       if (timeoutOrExpirationDate is! DateTime &&
-          timeoutOrExpirationDate is! num) {
+          timeoutOrExpirationDate is! num &&
+          timeoutOrExpirationDate != null) {
         throw ArgumentError('Invalid timeout or Expiration date');
       }
       return true;
@@ -1383,13 +1384,19 @@ class StreamChatClient {
           .toUtc();
     }
     return updateMessage(
-      message.copyWith(pinned: true, pinExpires: pinExpires),
+      message.copyWith(
+        pinned: true,
+        pinExpires: pinExpires,
+      ),
     );
   }
 
   /// Unpins provided message
-  Future<UpdateMessageResponse> unpinMessage(Message message) =>
-      updateMessage(message.copyWith(pinned: false));
+  Future<UpdateMessageResponse> unpinMessage(Message message) => updateMessage(
+        message.copyWith(
+          pinned: false,
+        ),
+      );
 }
 
 /// The class that handles the state of the channel listening to the events
diff --git a/packages/stream_chat/test/src/api/channel_test.dart b/packages/stream_chat/test/src/api/channel_test.dart
index c3409b7e..f92b05bb 100644
--- a/packages/stream_chat/test/src/api/channel_test.dart
+++ b/packages/stream_chat/test/src/api/channel_test.dart
@@ -449,6 +449,51 @@ void main() {
             .called(1);
       });
 
+      test('should be pinned successfully with null timeout', () async {
+        final mockDio = MockDio();
+
+        when(() => mockDio.options).thenReturn(BaseOptions());
+        when(() => mockDio.interceptors).thenReturn(Interceptors());
+
+        final client = StreamChatClient(
+          'api-key',
+          httpClient: mockDio,
+          tokenProvider: (_) async => '',
+        );
+        final channelClient = client.channel('messaging', id: 'testid');
+        final message = Message(text: 'Hello', id: 'test');
+
+        when(() => mockDio.post<String>(
+              any(),
+              data: any(named: 'data'),
+            )).thenAnswer((_) async => Response(
+              data: jsonEncode(ChannelState()),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ));
+
+        await channelClient.watch();
+
+        when(
+          () => mockDio.post<String>(
+            '/messages/${message.id}',
+            data: anything,
+          ),
+        ).thenAnswer(
+          (_) async => Response(
+            data: jsonEncode({'message': message}),
+            statusCode: 200,
+            requestOptions: FakeRequestOptions(),
+          ),
+        );
+
+        await channelClient.pinMessage(message);
+
+        verify(() =>
+                mockDio.post<String>('/messages/${message.id}', data: anything))
+            .called(1);
+      });
+
       test('should be unpinned successfully', () async {
         final mockDio = MockDio();
 
diff --git a/packages/stream_chat/test/src/client_test.dart b/packages/stream_chat/test/src/client_test.dart
index b2a5bbac..53792764 100644
--- a/packages/stream_chat/test/src/client_test.dart
+++ b/packages/stream_chat/test/src/client_test.dart
@@ -1112,6 +1112,28 @@ void main() {
               data: {'message': anything})).called(1);
         });
 
+        test('should complete successfully with a null value', () async {
+          final message = Message(text: 'Hello');
+
+          when(
+            () => mockDio.post<String>(
+              '/messages/${message.id}',
+              data: anything,
+            ),
+          ).thenAnswer(
+            (_) async => Response(
+              data: jsonEncode({'message': message}),
+              statusCode: 200,
+              requestOptions: FakeRequestOptions(),
+            ),
+          );
+
+          await client.pinMessage(message);
+
+          verify(() => mockDio.post<String>('/messages/${message.id}',
+              data: {'message': anything})).called(1);
+        });
+
         test('should unpin message successfully', () async {
           final message = Message(text: 'Hello');