diff --git a/test/cpp_extensions/python_agnostic_extension/python_agnostic/csrc/ultra_norm.cu b/test/cpp_extensions/python_agnostic_extension/python_agnostic/csrc/ultra_norm.cu
index 5abf7c9f4717a..6770ef9192625 100644
--- a/test/cpp_extensions/python_agnostic_extension/python_agnostic/csrc/ultra_norm.cu
+++ b/test/cpp_extensions/python_agnostic_extension/python_agnostic/csrc/ultra_norm.cu
@@ -2,7 +2,7 @@
 #include <ATen/ops/cat_cuda_dispatch.h>
 #include <ATen/ops/norm_cuda_dispatch.h>
 #include <ATen/ops/unsqueeze.h>
-#include <torch/extension.h>
+#include <torch/library.h>
 
 at::Tensor ultra_norm(at::TensorList inputs) {
     auto res = at::native::foreach_tensor_norm_cuda(inputs);
diff --git a/torch/utils/cpp_extension.py b/torch/utils/cpp_extension.py
index 3515e4a75e34e..67f58004ffdbf 100644
--- a/torch/utils/cpp_extension.py
+++ b/torch/utils/cpp_extension.py
@@ -289,6 +289,8 @@ def _join_sycl_home(*paths) -> str:
     'win-amd64' : 'x86_amd64',
 }
 
+min_supported_cpython = "0x03090000"  # Python 3.9 hexcode
+
 def get_cxx_compiler():
     if IS_WINDOWS:
         compiler = os.environ.get('CXX', 'cl')
@@ -573,11 +575,22 @@ def build_extensions(self) -> None:
                         extension.extra_compile_args[ext] = []
 
             self._add_compile_flag(extension, '-DTORCH_API_INCLUDE_EXTENSION_H')
-            # See note [Pybind11 ABI constants]
-            for name in ["COMPILER_TYPE", "STDLIB", "BUILD_ABI"]:
-                val = getattr(torch._C, f"_PYBIND11_{name}")
-                if val is not None and not IS_WINDOWS:
-                    self._add_compile_flag(extension, f'-DPYBIND11_{name}="{val}"')
+
+            if extension.py_limited_api:
+                # compile any extension that has passed in py_limited_api to the
+                # Extension constructor with the Py_LIMITED_API flag set to our
+                # min supported CPython version.
+                # See https://docs.python.org/3/c-api/stable.html#c.Py_LIMITED_API
+                self._add_compile_flag(extension, f'-DPy_LIMITED_API={min_supported_cpython}')
+            else:
+                # pybind11 is not CPython API stable so don't add these flags used when
+                # compiling pybind11 when pybind11 is not even used. otherwise, the build
+                # logs are confusing.
+                # See note [Pybind11 ABI constants]
+                for name in ["COMPILER_TYPE", "STDLIB", "BUILD_ABI"]:
+                    val = getattr(torch._C, f"_PYBIND11_{name}")
+                    if val is not None and not IS_WINDOWS:
+                        self._add_compile_flag(extension, f'-DPYBIND11_{name}="{val}"')
             self._define_torch_extension_name(extension)
             self._add_gnu_cpp_abi_flag(extension)
 
@@ -972,7 +985,7 @@ def CppExtension(name, sources, *args, **kwargs):
     constructor. Full list arguments can be found at
     https://setuptools.pypa.io/en/latest/userguide/ext_modules.html#extension-api-reference
 
-    .. note::
+    .. warning::
         The PyTorch python API (as provided in libtorch_python) cannot be built
         with the flag ``py_limited_api=True``.  When this flag is passed, it is
         the user's responsibility in their library to not use APIs from
@@ -981,6 +994,14 @@ def CppExtension(name, sources, *args, **kwargs):
         example, to give access to custom ops from python, the library should
         register the ops through the dispatcher.
 
+        Contrary to CPython setuptools, who does not define -DPy_LIMITED_API
+        as a compile flag when py_limited_api is specified as an option for
+        the "bdist_wheel" command in ``setup``, PyTorch does! We will specify
+        -DPy_LIMITED_API=min_supported_cpython to best enforce consistency,
+        safety, and sanity in order to encourage best practices. To target a
+        different version, set min_supported_cpython to the hexcode of the
+        CPython version of choice.
+
     Example:
         >>> # xdoctest: +SKIP
         >>> # xdoctest: +REQUIRES(env:TORCH_DOCTEST_CPP_EXT)
@@ -1036,7 +1057,7 @@ def CUDAExtension(name, sources, *args, **kwargs):
     constructor. Full list arguments can be found at
     https://setuptools.pypa.io/en/latest/userguide/ext_modules.html#extension-api-reference
 
-    .. note::
+    .. warning::
         The PyTorch python API (as provided in libtorch_python) cannot be built
         with the flag ``py_limited_api=True``.  When this flag is passed, it is
         the user's responsibility in their library to not use APIs from
@@ -1045,6 +1066,14 @@ def CUDAExtension(name, sources, *args, **kwargs):
         example, to give access to custom ops from python, the library should
         register the ops through the dispatcher.
 
+        Contrary to CPython setuptools, who does not define -DPy_LIMITED_API
+        as a compile flag when py_limited_api is specified as an option for
+        the "bdist_wheel" command in ``setup``, PyTorch does! We will specify
+        -DPy_LIMITED_API=min_supported_cpython to best enforce consistency,
+        safety, and sanity in order to encourage best practices. To target a
+        different version, set min_supported_cpython to the hexcode of the
+        CPython version of choice.
+
     Example:
         >>> # xdoctest: +SKIP
         >>> # xdoctest: +REQUIRES(env:TORCH_DOCTEST_CPP_EXT)
@@ -1408,10 +1437,6 @@ def _get_pybind11_abi_build_flags():
     # that can cause a hard to debug segfaults.
     # For PyTorch extensions we want to relax those restrictions and pass compiler, stdlib and abi properties
     # captured during PyTorch native library compilation in torch/csrc/Module.cpp
-    #
-    # Note that these flags don't have side effects even if the PyTorch extension does not
-    # require nor use pybind, so we do not do anything differently for them in the py_limited_api
-    # case.
 
     abi_cflags = []
     for pname in ["COMPILER_TYPE", "STDLIB", "BUILD_ABI"]: