diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 20db7747d5db13..78c892f2094e7f 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -1586,8 +1586,12 @@ def _wait(self, timeout):
             """Internal implementation of wait() on Windows."""
             if timeout is None:
                 timeout_millis = _winapi.INFINITE
+            elif timeout <= 0:
+                timeout_millis = 0
             else:
                 timeout_millis = int(timeout * 1000)
+                if timeout_millis >= _winapi.INFINITE:
+                    raise OverflowError('timeout too large to convert to C DWORD')
             if self.returncode is None:
                 # API note: Returns immediately if timeout_millis == 0.
                 result = _winapi.WaitForSingleObject(self._handle,