diff --git a/tox.ini b/tox.ini
index ab2dbb8b14d..9b412aab001 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,6 +8,7 @@ envlist = py35,py27,compliance,pep8
 # random hash seed successfully.
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
+         PYTHONWARNINGS=default::DeprecationWarning
 usedevelop = True
 install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}