diff --git a/changelog.d/4392.bugfix b/changelog.d/4392.bugfix
new file mode 100644
index 0000000000..2223f7dcd6
--- /dev/null
+++ b/changelog.d/4392.bugfix
@@ -0,0 +1 @@
+Fix typo in ALL_USER_TYPES definition to ensure type is a tuple
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 87bc1cb53d..022f772714 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -128,4 +128,4 @@ class UserTypes(object):
     'admin' and 'guest' users should also be UserTypes. Normal users are type None
     """
     SUPPORT = "support"
-    ALL_USER_TYPES = (SUPPORT)
+    ALL_USER_TYPES = (SUPPORT,)