diff --git a/changelog.d/14727.bugfix b/changelog.d/14727.bugfix
new file mode 100644
index 0000000000..25079496e4
--- /dev/null
+++ b/changelog.d/14727.bugfix
@@ -0,0 +1 @@
+Remove the unspecced `device` field from `/pushrules` responses.
diff --git a/synapse/push/clientformat.py b/synapse/push/clientformat.py
index 622a1e35c5..bb76c169c6 100644
--- a/synapse/push/clientformat.py
+++ b/synapse/push/clientformat.py
@@ -26,10 +26,7 @@ def format_push_rules_for_user(
     """Converts a list of rawrules and a enabled map into nested dictionaries
     to match the Matrix client-server format for push rules"""
 
-    rules: Dict[str, Dict[str, List[Dict[str, Any]]]] = {
-        "global": {},
-        "device": {},
-    }
+    rules: Dict[str, Dict[str, List[Dict[str, Any]]]] = {"global": {}}
 
     rules["global"] = _add_empty_priority_class_arrays(rules["global"])