diff --git a/radicale/tests/test_auth.py b/radicale/tests/test_auth.py
index 408ad3f0..e7e15a47 100644
--- a/radicale/tests/test_auth.py
+++ b/radicale/tests/test_auth.py
@@ -301,7 +301,7 @@ class TestBaseAuthRequests(BaseTest):
         delay = .3
         delay_min = delay * 0.9  # no random jitter during test
         delay_max = delay + 0.2  # no random jitter during test
-        if sys.platform == "darwin":  # no reliable sleep times
+        if sys.platform == "darwin" or sys.platform == 'win32':  # no reliable sleep times
             delay_max = delay_max * 1.5
 
         time_begin = datetime.datetime.now()