diff --git a/tests/rest/synapse/__init__.py b/tests/rest/synapse/__init__.py
new file mode 100644
index 00000000000..e5138f67e12
--- /dev/null
+++ b/tests/rest/synapse/__init__.py
@@ -0,0 +1,12 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2024 New Vector, Ltd
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# See the GNU Affero General Public License for more details:
+# <https://www.gnu.org/licenses/agpl-3.0.html>.
diff --git a/tests/rest/synapse/client/__init__.py b/tests/rest/synapse/client/__init__.py
new file mode 100644
index 00000000000..e5138f67e12
--- /dev/null
+++ b/tests/rest/synapse/client/__init__.py
@@ -0,0 +1,12 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2024 New Vector, Ltd
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# See the GNU Affero General Public License for more details:
+# <https://www.gnu.org/licenses/agpl-3.0.html>.
diff --git a/tests/rest/synapse/client/test_federation_whitelist.py b/tests/rest/synapse/client/test_federation_whitelist.py
new file mode 100644
index 00000000000..0363ad9694c
--- /dev/null
+++ b/tests/rest/synapse/client/test_federation_whitelist.py
@@ -0,0 +1,95 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2024 New Vector, Ltd
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# See the GNU Affero General Public License for more details:
+# <https://www.gnu.org/licenses/agpl-3.0.html>.
+
+from typing import Dict
+
+from twisted.web.resource import Resource
+
+from synapse.rest import admin
+from synapse.rest.client import login
+from synapse.rest.synapse.client import build_synapse_client_resource_tree
+
+from tests import unittest
+
+
+class FederationWhitelistTests(unittest.HomeserverTestCase):
+    servlets = [
+        admin.register_servlets_for_client_rest_resource,
+        login.register_servlets,
+    ]
+
+    def create_resource_dict(self) -> Dict[str, Resource]:
+        base = super().create_resource_dict()
+        base.update(build_synapse_client_resource_tree(self.hs))
+        return base
+
+    def test_default(self) -> None:
+        "By default the endpoint should 404"
+        channel = self.make_request(
+            "GET", "/_synapse/client/config/federation_whitelist", shorthand=False
+        )
+
+        self.assertEqual(channel.code, 404)
+
+    @unittest.override_config({"extension_federation_whitelist_endpoint": True})
+    def test_no_auth(self) -> None:
+        "Endpoint requires auth when enabled"
+
+        channel = self.make_request(
+            "GET", "/_synapse/client/config/federation_whitelist", shorthand=False
+        )
+
+        self.assertEqual(channel.code, 401)
+
+    @unittest.override_config({"extension_federation_whitelist_endpoint": True})
+    def test_no_whitelist(self) -> None:
+        "Test when there is no whitelist configured"
+
+        self.register_user("user", "password")
+        tok = self.login("user", "password")
+
+        channel = self.make_request(
+            "GET",
+            "/_synapse/client/config/federation_whitelist",
+            shorthand=False,
+            access_token=tok,
+        )
+
+        self.assertEqual(channel.code, 200)
+        self.assertEqual(
+            channel.json_body, {"whitelist_enabled": False, "whitelist": []}
+        )
+
+    @unittest.override_config(
+        {
+            "extension_federation_whitelist_endpoint": True,
+            "federation_domain_whitelist": ["example.com"],
+        }
+    )
+    def test_whitelist(self) -> None:
+        "Test when there is a whitelist configured"
+
+        self.register_user("user", "password")
+        tok = self.login("user", "password")
+
+        channel = self.make_request(
+            "GET",
+            "/_synapse/client/config/federation_whitelist",
+            shorthand=False,
+            access_token=tok,
+        )
+
+        self.assertEqual(channel.code, 200)
+        self.assertEqual(
+            channel.json_body, {"whitelist_enabled": True, "whitelist": ["example.com"]}
+        )