diff --git a/tox.ini b/tox.ini
index 217cd1feb..fea21e1a9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,7 +5,14 @@ envlist = docs,flake8,mypy,coverage,py{35,36,37,38,39},du{12,13,14,15}
 [testenv]
 usedevelop = True
 passenv =
-    https_proxy http_proxy no_proxy PERL PERL5LIB PYTEST_ADDOPTS EPUBCHECK_PATH
+    https_proxy
+    http_proxy
+    no_proxy
+    PERL
+    PERL5LIB
+    PYTEST_ADDOPTS
+    EPUBCHECK_PATH
+    TERM
 description =
     py{35,36,37,38,39}: Run unit tests against {envname}.
     du{12,13,14}: Run unit tests with the given version of docutils.