diff --git a/Source/MQTTnet/Adapter/MqttChannelAdapter.cs b/Source/MQTTnet/Adapter/MqttChannelAdapter.cs
index 4a0a85d..81394da 100644
--- a/Source/MQTTnet/Adapter/MqttChannelAdapter.cs
+++ b/Source/MQTTnet/Adapter/MqttChannelAdapter.cs
@@ -274,6 +274,7 @@ namespace MQTTnet.Adapter
             _isDisposed = true;
 
             _channel?.Dispose();
+            _writerSemaphore?.Dispose();
         }
 
         private void ThrowIfDisposed()