diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 4507fbc8164dc8..8d92ac3957c8a5 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -4165,6 +4165,11 @@ written in Python, such as a mail server's external command delivery program.
       If you use TLS sockets in an application calling ``fork()``, see
       the warning in the :mod:`ssl` documentation.
 
+   .. warning::
+
+      On macOS the use of this function is unsafe when mixed with using
+      higher-level system APIs, and that includes using :mod:`urllib.request`.
+
    .. versionchanged:: 3.8
       Calling ``fork()`` in a subinterpreter is no longer supported
       (:exc:`RuntimeError` is raised).
@@ -4204,6 +4209,11 @@ written in Python, such as a mail server's external command delivery program.
 
    .. audit-event:: os.forkpty "" os.forkpty
 
+   .. warning::
+
+      On macOS the use of this function is unsafe when mixed with using
+      higher-level system APIs, and that includes using :mod:`urllib.request`.
+
    .. versionchanged:: 3.12
       If Python is able to detect that your process has multiple
       threads, this now raises a :exc:`DeprecationWarning`. See the
diff --git a/Doc/library/pty.rst b/Doc/library/pty.rst
index af9378464edb9f..bd2f5ed45cb8b4 100644
--- a/Doc/library/pty.rst
+++ b/Doc/library/pty.rst
@@ -33,6 +33,9 @@ The :mod:`pty` module defines the following functions:
    file descriptor connected to the child's controlling terminal (and also to the
    child's standard input and output).
 
+   .. warning:: On macOS the use of this function is unsafe when mixed with using
+      higher-level system APIs, and that includes using :mod:`urllib.request`.
+
 
 .. function:: openpty()
 
diff --git a/Doc/library/urllib.request.rst b/Doc/library/urllib.request.rst
index 690f01c93a1ee7..f55b6813d1e5bc 100644
--- a/Doc/library/urllib.request.rst
+++ b/Doc/library/urllib.request.rst
@@ -21,6 +21,14 @@ authentication, redirections, cookies and more.
     The `Requests package <https://requests.readthedocs.io/en/master/>`_
     is recommended for a higher-level HTTP client interface.
 
+.. warning::
+
+   On macOS it is unsafe to use this module in programs using
+   :func:`os.fork` because the :func:`getproxies` implementation for
+   macOS uses a higher-level system API. Set the environment variable
+   ``no_proxy`` to ``*`` to avoid this problem
+   (e.g. ``os.environ["no_proxy"] = "*"``).
+
 .. include:: ../includes/wasm-notavail.rst
 
 The :mod:`urllib.request` module defines the following functions: