diff --git a/stdlib/3/concurrent/futures/thread.pyi b/stdlib/3/concurrent/futures/thread.pyi
index 1774b639c..88a45a3e0 100644
--- a/stdlib/3/concurrent/futures/thread.pyi
+++ b/stdlib/3/concurrent/futures/thread.pyi
@@ -1,5 +1,10 @@
 from typing import Optional
 from ._base import Executor, Future
+import sys
 
 class ThreadPoolExecutor(Executor):
-    def __init__(self, max_workers: Optional[int] = ...) -> None: ...
+    if sys.version_info >= (3, 6):
+        def __init__(self, max_workers: Optional[int] = ...,
+                     thread_name_prefix: str = ...) -> None: ...
+    else:
+        def __init__(self, max_workers: Optional[int] = ...) -> None: ...