diff --git a/tox.ini b/tox.ini
index 56f80b1c..3256e11e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,6 +13,7 @@ deps =
      -r{toxinidir}/requirements.txt
      -r{toxinidir}/test-requirements.txt
 commands = python setup.py test --slowest --testr-args='{posargs}'
+passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 
 [testenv:pep8]
 whitelist_externals = bash