diff --git a/monkeypatch.py b/monkeypatch.py
index 1a0b74a..a088f3b 100644
--- a/monkeypatch.py
+++ b/monkeypatch.py
@@ -29,6 +29,8 @@ if libc_path == 'libc.so.6':
     sleep = posixsleep
 elif libc_path == 'kernel32':
     sleep = ntsleep
+elif libc_path == "libSystem.dylib":
+    sleep = posixsleep
 else:
     print("Couldn't figure out how to use native sleep calls with "+str(libc_path)+", event loop performance may suffer.")
     sleep = time.sleep
\ No newline at end of file