diff --git a/docs/topics/testing.txt b/docs/topics/testing.txt
index 7afdbe88cc2..117dfbe5912 100644
--- a/docs/topics/testing.txt
+++ b/docs/topics/testing.txt
@@ -508,6 +508,13 @@ file, all Django tests run with :setting:`DEBUG`\=False. This is to ensure that
 the observed output of your code matches what will be seen in a production
 setting.
 
+Caches are not cleared after each test, and running "manage.py test fooapp" can
+insert data from the tests into the cache of a live system if you run your
+tests in production because, unlike databases, a separate "test cache" is not
+used. This behavior `may change`_ in the future.
+
+.. _may change: https://code.djangoproject.com/ticket/11505
+
 Understanding the test output
 -----------------------------