diff --git a/tox.ini b/tox.ini
index b9ed6c9db9..e424d9adf3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,4 +1,4 @@
-# Tox (http://tox.testrun.org/) is a tool for running tests in multiple
+# Tox (https://tox.readthedocs.io/) is a tool for running tests in multiple
 # virtualenvs. This configuration file helps to run the test suite on all
 # supported Python versions. To use it, "pip install tox" and then run "tox"
 # from this directory.