diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 09a7aad..7ddb7a9 100755
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -142,6 +142,7 @@
 }
 
 $test_list = simpletest_script_get_test_list();
+shuffle($test_list);
 
 // Try to allocate unlimited time to run the tests.
 drupal_set_time_limit(0);