diff --git a/tox.ini b/tox.ini
index 1e4530f07..e4d56260b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,6 +9,7 @@ usedevelop = True
 install_command = pip install -U --force-reinstall {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          PYTHONDONTWRITEBYTECODE = 1
+passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 deps = -r{toxinidir}/test-requirements.txt
 commands =
   find . -type f -name "*.pyc" -delete