diff --git a/changelog.d/12250.feature b/changelog.d/12250.feature
new file mode 100644
index 000000000..29a272445
--- /dev/null
+++ b/changelog.d/12250.feature
@@ -0,0 +1 @@
+Allow registering admin users using the module API. Contributed by Famedly.
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index aa8256b36..a628faaf6 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -611,15 +611,18 @@ class ModuleApi:
         localpart: str,
         displayname: Optional[str] = None,
         emails: Optional[List[str]] = None,
+        admin: bool = False,
     ) -> "defer.Deferred[str]":
         """Registers a new user with given localpart and optional displayname, emails.
 
         Added in Synapse v1.2.0.
+        Changed in Synapse v1.56.0: add 'admin' argument to register the user as admin.
 
         Args:
             localpart: The localpart of the new user.
             displayname: The displayname of the new user.
             emails: Emails to bind to the new user.
+            admin: True if the user should be registered as a server admin.
 
         Raises:
             SynapseError if there is an error performing the registration. Check the
@@ -633,6 +636,7 @@ class ModuleApi:
                 localpart=localpart,
                 default_display_name=displayname,
                 bind_emails=emails or [],
+                admin=admin,
             )
         )
 
diff --git a/tests/module_api/test_api.py b/tests/module_api/test_api.py
index c3f20f969..10dd94b54 100644
--- a/tests/module_api/test_api.py
+++ b/tests/module_api/test_api.py
@@ -86,6 +86,16 @@ class ModuleApiTestCase(HomeserverTestCase):
         displayname = self.get_success(self.store.get_profile_displayname("bob"))
         self.assertEqual(displayname, "Bobberino")
 
+    def test_can_register_admin_user(self):
+        user_id = self.get_success(
+            self.register_user(
+                "bob_module_admin", "1234", displayname="Bobberino Admin", admin=True
+            )
+        )
+        found_user = self.get_success(self.module_api.get_userinfo_by_id(user_id))
+        self.assertEqual(found_user.user_id.to_string(), user_id)
+        self.assertIdentical(found_user.is_admin, True)
+
     def test_get_userinfo_by_id(self):
         user_id = self.register_user("alice", "1234")
         found_user = self.get_success(self.module_api.get_userinfo_by_id(user_id))