diff --git a/setup.py b/setup.py
index 3db2fd4c..68481d4d 100644
--- a/setup.py
+++ b/setup.py
@@ -27,7 +27,8 @@ required = [
     'pip>=9.0.1',
     'pip-tools>=1.9.0',
     'requests>2.18.0',
-    'flake8'
+    'flake8',
+    'urllib3'
 ]
 
 if sys.version_info < (2, 7):