diff --git a/migrations/20260205021933-create-unique-index-folders-parentuuid-plainname.js b/migrations/20260205021933-create-unique-index-folders-parentuuid-plainname.js
new file mode 100644
index 000000000..c67e05b41
--- /dev/null
+++ b/migrations/20260205021933-create-unique-index-folders-parentuuid-plainname.js
@@ -0,0 +1,18 @@
+'use strict';
+
+/** @type {import('sequelize-cli').Migration} */
+module.exports = {
+  up: async (queryInterface) => {
+    await queryInterface.sequelize.query(`
+      CREATE UNIQUE INDEX CONCURRENTLY folders_parentuuid_plainname_unique
+      ON folders (parent_uuid, plain_name)
+      WHERE deleted = false;
+    `);
+  },
+
+  down: async (queryInterface) => {
+    await queryInterface.sequelize.query(`
+      DROP INDEX CONCURRENTLY IF EXISTS folders_parentuuid_plainname_unique;
+    `);
+  },
+};