diff --git a/src/include/lwip/apps/mqtt.h b/src/include/lwip/apps/mqtt.h
index 3d3fcb74..ce8c6ca7 100644
--- a/src/include/lwip/apps/mqtt.h
+++ b/src/include/lwip/apps/mqtt.h
@@ -46,6 +46,8 @@ extern "C" {
 
 typedef struct mqtt_client_t mqtt_client_t;
 
+/** @ingroup mqtt
+ * Default MQTT port */
 #define MQTT_PORT 1883
 
 /*---------------------------------------------------------------------------------------------- */