diff --git a/changelogs/client_server/newsfragments/1535.clarification b/changelogs/client_server/newsfragments/1535.clarification
new file mode 100644
index 000000000..805f6b56c
--- /dev/null
+++ b/changelogs/client_server/newsfragments/1535.clarification
@@ -0,0 +1 @@
+Add missing `knock_restricted` join rule to the `m.room.join_rules` schema.
diff --git a/data/event-schemas/schema/m.room.join_rules.yaml b/data/event-schemas/schema/m.room.join_rules.yaml
index d5f8eb2de..b6a322c66 100644
--- a/data/event-schemas/schema/m.room.join_rules.yaml
+++ b/data/event-schemas/schema/m.room.join_rules.yaml
@@ -28,6 +28,7 @@ properties:
           - invite
           - private
           - restricted
+          - knock_restricted
         type: string
       allow:
         x-addedInMatrixVersion: "1.2"