diff --git a/setup.py b/setup.py
index 85a28d82..be548d2f 100644
--- a/setup.py
+++ b/setup.py
@@ -73,7 +73,7 @@ def read(path):
             "stopit>=1.1.2,<2",
             "pytz",
             "zc.customdoctests>=1.0.1,<2",
-            "zope.testing>=4,<6",
+            "zope.testing>=4,<7",
             "zope.testrunner>=5,<8",
         ],
     },