diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index 13154b1723..bcb8f33a58 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -99,7 +99,7 @@ class EventBase(object):
 
         return d
 
-    def get(self, key, default):
+    def get(self, key, default=None):
         return self._event_dict.get(key, default)
 
     def get_internal_metadata_dict(self):