diff --git a/Doc/library/ctypes.rst b/Doc/library/ctypes.rst
index b186f1d5753a65..c10e54f153243f 100644
--- a/Doc/library/ctypes.rst
+++ b/Doc/library/ctypes.rst
@@ -1320,7 +1320,7 @@ There are several ways to load shared libraries into the Python process.  One
 way is to instantiate one of the following classes:
 
 
-.. class:: CDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=0)
+.. class:: CDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=None)
 
    Instances of this class represent loaded shared libraries. Functions in these
    libraries use the standard C calling convention, and are assumed to return
@@ -1342,7 +1342,7 @@ way is to instantiate one of the following classes:
     -- A tool to find DLL dependents.
 
 
-.. class:: OleDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=0)
+.. class:: OleDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=None)
 
    Windows only: Instances of this class represent loaded shared libraries,
    functions in these libraries use the ``stdcall`` calling convention, and are
@@ -1355,7 +1355,7 @@ way is to instantiate one of the following classes:
       :exc:`WindowsError` used to be raised.
 
 
-.. class:: WinDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=0)
+.. class:: WinDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False, winmode=None)
 
    Windows only: Instances of this class represent loaded shared libraries,
    functions in these libraries use the ``stdcall`` calling convention, and are