diff --git a/changelog.d/12020.feature b/changelog.d/12020.feature
new file mode 100644
index 000000000000..1ac9d2060e2a
--- /dev/null
+++ b/changelog.d/12020.feature
@@ -0,0 +1 @@
+Advertise Matrix 1.1 support on `/_matrix/client/versions`.
\ No newline at end of file
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 2290c57c126e..35b88e9bbf14 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -73,6 +73,7 @@ def on_GET(self, request: Request) -> Tuple[int, JsonDict]:
                     "r0.5.0",
                     "r0.6.0",
                     "r0.6.1",
+                    "v1.1",
                 ],
                 # as per MSC1497:
                 "unstable_features": {