diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py
index 768119c4c87..2614689bca9 100644
--- a/Lib/test/test_multiprocessing.py
+++ b/Lib/test/test_multiprocessing.py
@@ -757,7 +757,13 @@ def test_notify_all(self):
         cond.release()
 
         # check they have all woken
-        time.sleep(DELTA)
+        for i in range(10):
+            try:
+                if get_value(woken) == 6:
+                    break
+            except NotImplementedError:
+                break
+            time.sleep(DELTA)
         self.assertReturnsIfImplemented(6, get_value, woken)
 
         # check state is not mucked up
diff --git a/Misc/NEWS b/Misc/NEWS
index f5f08e431b0..fa8f039b82c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -269,6 +269,8 @@ Extensions
 Tests
 -----
 
+- Issue #11790: Fix sporadic failures in test_multiprocessing.WithProcessesTestCondition.
+
 - Fix possible "file already exists" error when running the tests in parallel.
 
 - Issue #11719: Fix message about unexpected test_msilib skip on non-Windows