diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py
index 0631df4bfcb0..00222a558670 100644
--- a/synapse/storage/databases/main/stream.py
+++ b/synapse/storage/databases/main/stream.py
@@ -45,7 +45,6 @@
     Optional,
     Set,
     Tuple,
-    Union,
 )
 
 import attr