diff --git a/.changeset/smooth-mirrors-bow.md b/.changeset/smooth-mirrors-bow.md
new file mode 100644
index 00000000..504fc304
--- /dev/null
+++ b/.changeset/smooth-mirrors-bow.md
@@ -0,0 +1,5 @@
+---
+'@capacitor-firebase/analytics': patch
+---
+
+fix(web): `setUserId(...)` has set an empty string instead of `null`
diff --git a/packages/analytics/src/web.ts b/packages/analytics/src/web.ts
index f1a5c756..204af69f 100644
--- a/packages/analytics/src/web.ts
+++ b/packages/analytics/src/web.ts
@@ -60,7 +60,7 @@ export class FirebaseAnalyticsWeb
 
   public async setUserId(options: SetUserIdOptions): Promise<void> {
     const analytics = getAnalytics();
-    setUserId(analytics, options.userId || '');
+    setUserId(analytics, options.userId);
   }
 
   public async setUserProperty(options: SetUserPropertyOptions): Promise<void> {