diff --git a/tox.ini b/tox.ini
index 4fab6b6..cacc2d9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,6 +7,7 @@ envlist = py26,py27,pep8
 usedevelop = True
 install_command = pip install --allow-external -U {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
+passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 deps =
     -r{toxinidir}/test-requirements.txt
 commands =