diff --git a/changelog.d/5804.bugfix b/changelog.d/5804.bugfix
new file mode 100644
index 000000000000..75c17b460dbb
--- /dev/null
+++ b/changelog.d/5804.bugfix
@@ -0,0 +1 @@
+Fix check that tombstone is a state event in push rules.
diff --git a/synapse/push/baserules.py b/synapse/push/baserules.py
index 134bf805eb8d..286374d0b537 100644
--- a/synapse/push/baserules.py
+++ b/synapse/push/baserules.py
@@ -245,7 +245,13 @@ def make_base_prepend_rules(kind, modified_base_rules):
                 "key": "type",
                 "pattern": "m.room.tombstone",
                 "_id": "_tombstone",
-            }
+            },
+            {
+                "kind": "event_match",
+                "key": "state_key",
+                "pattern": "",
+                "_id": "_tombstone_statekey",
+            },
         ],
         "actions": ["notify", {"set_tweak": "highlight", "value": True}],
     },