diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index c04905dfed..eb279579e7 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -328,7 +328,7 @@ class EventBase(metaclass=abc.ABCMeta):
         self._encoded_dict = _encode_dict(event_dict)
 
         self.depth = event_dict["depth"]
-        self.origin = event_dict["origin"]
+        self.origin = event_dict.get("origin")
         self.origin_server_ts = event_dict["origin_server_ts"]
         self.redacts = event_dict.get("redacts")
         self.room_id = event_dict["room_id"]