diff --git a/tox.ini b/tox.ini
index 70f3c0905..3a7c5bfaa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,6 +8,7 @@ usedevelop = True
 install_command = pip install -U -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
+   PYTHONWARNINGS=default::DeprecationWarning
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands = python setup.py test --slowest --testr-args='{posargs}'