diff --git a/browser/base/content/test/browser_social_shareButton.js b/browser/base/content/test/browser_social_shareButton.js
index f425b8d61db..5a8d163c768 100644
--- a/browser/base/content/test/browser_social_shareButton.js
+++ b/browser/base/content/test/browser_social_shareButton.js
@@ -20,6 +20,7 @@ function test() {
   }, true);
 
   registerCleanupFunction(function() {
+    Services.prefs.clearUserPref(prefName);
     gBrowser.removeTab(tab);
   });
 }