diff --git a/Lib/sched.py b/Lib/sched.py
index 5292fcf..bd1f427 100644
--- a/Lib/sched.py
+++ b/Lib/sched.py
@@ -30,8 +30,11 @@
 
 import time
 import heapq
-import threading
 from collections import namedtuple
+try:
+    import threading
+except ImportError:
+    import dummy_threading as threading
 
 __all__ = ["scheduler"]