diff --git a/src/azure-cli-core/tox.ini b/src/azure-cli-core/tox.ini
index 934229876c6..42fe1cb844b 100644
--- a/src/azure-cli-core/tox.ini
+++ b/src/azure-cli-core/tox.ini
@@ -5,6 +5,7 @@ skip_missing_interpreters = True
 [testenv]
 deps = pytest
        mock
+       pip==18.1
        azure-mgmt-resource==2.1.0
        azure-mgmt-monitor==0.5.0
        -e ../azure-cli-telemetry