diff --git a/src/ptvsd/common/util.py b/src/ptvsd/common/util.py
index 462679af..97ac3c05 100644
--- a/src/ptvsd/common/util.py
+++ b/src/ptvsd/common/util.py
@@ -4,7 +4,6 @@
 
 from __future__ import absolute_import, print_function, unicode_literals
 
-import threading
 import sys