diff --git a/.changeset/purple-turtles-float.md b/.changeset/purple-turtles-float.md
new file mode 100644
index 0000000000..8736a7315f
--- /dev/null
+++ b/.changeset/purple-turtles-float.md
@@ -0,0 +1,5 @@
+---
+'@backstage/core-api': patch
+---
+
+Delay auth loginPopup close to avoid race condition with callers of authFlowHelpers.
diff --git a/plugins/auth-backend/src/lib/flow/authFlowHelpers.ts b/plugins/auth-backend/src/lib/flow/authFlowHelpers.ts
index 22ffc7af88..e70aa0bfee 100644
--- a/plugins/auth-backend/src/lib/flow/authFlowHelpers.ts
+++ b/plugins/auth-backend/src/lib/flow/authFlowHelpers.ts
@@ -56,7 +56,9 @@ export const postMessageResponse = (
     var originInfo = {'type': 'config_info', 'targetOrigin': origin};
     (window.opener || window.parent).postMessage(originInfo, '*');
     (window.opener || window.parent).postMessage(JSON.parse(authResponse), origin);
-    window.close();
+    setTimeout(() => {
+      window.close();
+    }, 100); // same as the interval of the core-api lib/loginPopup.ts (to address race conditions)
   `;
   const hash = crypto.createHash('sha256').update(script).digest('base64');