diff --git a/Source/MQTTnet/Formatter/V5/MqttV500PacketEncoder.cs b/Source/MQTTnet/Formatter/V5/MqttV500PacketEncoder.cs
index bf978c4b..a6e259db 100644
--- a/Source/MQTTnet/Formatter/V5/MqttV500PacketEncoder.cs
+++ b/Source/MQTTnet/Formatter/V5/MqttV500PacketEncoder.cs
@@ -251,13 +251,18 @@ namespace MQTTnet.Formatter.V5
             var propertiesWriter = new MqttV500PropertiesWriter();
             if (packet.Properties != null)
             {
-                propertiesWriter.WritePayloadFormatIndicator(packet.Properties.PayloadFormatIndicator);
-                propertiesWriter.WriteMessageExpiryInterval(packet.Properties.MessageExpiryInterval);
-                propertiesWriter.WriteTopicAlias(packet.Properties.TopicAlias);
-                propertiesWriter.WriteResponseTopic(packet.Properties.ResponseTopic);
-                propertiesWriter.WriteCorrelationData(packet.Properties.CorrelationData);
-                propertiesWriter.WriteSubscriptionIdentifiers(packet.Properties.SubscriptionIdentifiers);
+                if (packet.Properties.TopicAlias == 0)
+                {
+                    throw new MqttProtocolViolationException("A Topic Alias of 0 is not permitted. A sender MUST NOT send a PUBLISH packet containing a Topic Alias which has the value 0 [MQTT-3.3.2-8].");
+                }
+
                 propertiesWriter.WriteContentType(packet.Properties.ContentType);
+                propertiesWriter.WriteCorrelationData(packet.Properties.CorrelationData);
+                propertiesWriter.WriteMessageExpiryInterval(packet.Properties.MessageExpiryInterval);
+                propertiesWriter.WritePayloadFormatIndicator(packet.Properties.PayloadFormatIndicator);
+                propertiesWriter.WriteResponseTopic(packet.Properties.ResponseTopic);
+                propertiesWriter.WriteSubscriptionIdentifiers(packet.Properties.SubscriptionIdentifiers);
+                propertiesWriter.WriteTopicAlias(packet.Properties.TopicAlias);
                 propertiesWriter.WriteUserProperties(packet.Properties.UserProperties);
             }
 
diff --git a/Source/MQTTnet/MqttApplicationMessageBuilder.cs b/Source/MQTTnet/MqttApplicationMessageBuilder.cs
index bc2d9b86..7e48531f 100644
--- a/Source/MQTTnet/MqttApplicationMessageBuilder.cs
+++ b/Source/MQTTnet/MqttApplicationMessageBuilder.cs
@@ -222,9 +222,14 @@ namespace MQTTnet
 
         public MqttApplicationMessage Build()
         {
-            if (string.IsNullOrEmpty(_topic))
+            if (!_topicAlias.HasValue && string.IsNullOrEmpty(_topic))
             {
-                throw new MqttProtocolViolationException("Topic is not set.");
+                throw new MqttProtocolViolationException("Topic or TopicAlias is not set.");
+            }
+
+            if (_topicAlias == 0)
+            {
+                throw new MqttProtocolViolationException("A Topic Alias of 0 is not permitted. A sender MUST NOT send a PUBLISH packet containing a Topic Alias which has the value 0 [MQTT-3.3.2-8].");
             }
 
             var applicationMessage = new MqttApplicationMessage