diff --git a/changelog.d/13843.removal b/changelog.d/13843.removal
new file mode 100644
index 000000000..f6caaa889
--- /dev/null
+++ b/changelog.d/13843.removal
@@ -0,0 +1 @@
+Remove the `complete_sso_login` method from the Module API which was deprecated in Synapse 1.13.0.
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 0327fc57a..eacd631ee 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -63,7 +63,6 @@ from synapse.http.server import finish_request, respond_with_html
 from synapse.http.site import SynapseRequest
 from synapse.logging.context import defer_to_thread
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage.roommember import ProfileInfo
 from synapse.types import JsonDict, Requester, UserID
 from synapse.util import stringutils as stringutils
 from synapse.util.async_helpers import delay_cancellation, maybe_awaitable
@@ -1687,41 +1686,10 @@ class AuthHandler:
             respond_with_html(request, 403, self._sso_account_deactivated_template)
             return
 
-        profile = await self.store.get_profileinfo(
+        user_profile_data = await self.store.get_profileinfo(
             UserID.from_string(registered_user_id).localpart
         )
 
-        self._complete_sso_login(
-            registered_user_id,
-            auth_provider_id,
-            request,
-            client_redirect_url,
-            extra_attributes,
-            new_user=new_user,
-            user_profile_data=profile,
-            auth_provider_session_id=auth_provider_session_id,
-        )
-
-    def _complete_sso_login(
-        self,
-        registered_user_id: str,
-        auth_provider_id: str,
-        request: Request,
-        client_redirect_url: str,
-        extra_attributes: Optional[JsonDict] = None,
-        new_user: bool = False,
-        user_profile_data: Optional[ProfileInfo] = None,
-        auth_provider_session_id: Optional[str] = None,
-    ) -> None:
-        """
-        The synchronous portion of complete_sso_login.
-
-        This exists purely for backwards compatibility of synapse.module_api.ModuleApi.
-        """
-
-        if user_profile_data is None:
-            user_profile_data = ProfileInfo(None, None)
-
         # Store any extra attributes which will be passed in the login response.
         # Note that this is per-user so it may overwrite a previous value, this
         # is considered OK since the newest SSO attributes should be most valid.
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index 87ba154cb..9287c0fb8 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -836,31 +836,6 @@ class ModuleApi:
             self._store.db_pool.runInteraction(desc, func, *args, **kwargs)  # type: ignore[arg-type]
         )
 
-    def complete_sso_login(
-        self, registered_user_id: str, request: SynapseRequest, client_redirect_url: str
-    ) -> None:
-        """Complete a SSO login by redirecting the user to a page to confirm whether they
-        want their access token sent to `client_redirect_url`, or redirect them to that
-        URL with a token directly if the URL matches with one of the whitelisted clients.
-
-        This is deprecated in favor of complete_sso_login_async.
-
-        Added in Synapse v1.11.1.
-
-        Args:
-            registered_user_id: The MXID that has been registered as a previous step of
-                of this SSO login.
-            request: The request to respond to.
-            client_redirect_url: The URL to which to offer to redirect the user (or to
-                redirect them directly if whitelisted).
-        """
-        self._auth_handler._complete_sso_login(
-            registered_user_id,
-            "<unknown>",
-            request,
-            client_redirect_url,
-        )
-
     async def complete_sso_login_async(
         self,
         registered_user_id: str,