diff --git a/crates/storage-pg/migrations/20260121104214_upstream_auth_user_session_fk_idx.sql b/crates/storage-pg/migrations/20260121104214_upstream_auth_user_session_fk_idx.sql
new file mode 100644
index 000000000..a5d3a2325
--- /dev/null
+++ b/crates/storage-pg/migrations/20260121104214_upstream_auth_user_session_fk_idx.sql
@@ -0,0 +1,11 @@
+-- no-transaction
+-- Copyright 2026 Element Creations Ltd.
+--
+-- SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+-- Please see LICENSE files in the repository root for full details.
+
+-- Adds an index on the user_session_id column on the
+-- upstream_oauth_authorization_sessions table
+CREATE INDEX CONCURRENTLY IF NOT EXISTS
+  upstream_oauth_authorization_sessions_user_session_id_idx
+  ON upstream_oauth_authorization_sessions (user_session_id);