diff --git a/dom/workers/test/xpcshell/xpcshell.ini b/dom/workers/test/xpcshell/xpcshell.ini
index 2acc533849c1..f84f665f4e4d 100644
--- a/dom/workers/test/xpcshell/xpcshell.ini
+++ b/dom/workers/test/xpcshell/xpcshell.ini
@@ -9,6 +9,7 @@ support-files =
 [test_workers.js]
 [test_fileReader.js]
 [test_remoteworker_launch_new_process.js]
+skip-if = appname = 'thunderbird' # Thunderbird doesn't use e10s.
 # The following firefox-appdir make sure that this xpcshell test will run
 # with e10s enabled (which is needed to make sure that the test case is
 # going to launch the expected new processes)