diff --git a/tox.ini b/tox.ini
index eb8dc7d5..ab0d6b44 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,6 +20,7 @@ deps =
 commands =
     !minreqs: pytest {posargs:--cov=linkcheck}
     minreqs: pytest {posargs:--cov=linkcheck -c pytest-minreqs.ini}
+passenv = CI
 setenv =
     LC_ALL=en_US.utf-8