diff --git a/pyproject.toml b/pyproject.toml
index 562c9d579..99aaad07d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,39 @@
 [build-system]
-requires = ['setuptools >= 40.8.0', 'wheel']
-build-backend = 'setuptools.build_meta'
+requires = ["flit_core >=3.3"]
+build-backend = "flit_core.buildapi"
+
+
+[project]
+name = "packaging"
+description = "Core utilities for Python packages"
+version = "21.4.dev0"
+readme = "README.rst"
+requires-python = ">=3.7"
+authors = [{name = "Donald Stufft", email = "donald@stufft.io"}]
+classifiers = [
+  "Development Status :: 5 - Production/Stable",
+  "Intended Audience :: Developers",
+  "License :: OSI Approved :: Apache Software License",
+  "License :: OSI Approved :: BSD License",
+  "Programming Language :: Python",
+  "Programming Language :: Python :: 3",
+  "Programming Language :: Python :: 3 :: Only",
+  "Programming Language :: Python :: 3.7",
+  "Programming Language :: Python :: 3.8",
+  "Programming Language :: Python :: 3.9",
+  "Programming Language :: Python :: 3.10",
+  "Programming Language :: Python :: Implementation :: CPython",
+  "Programming Language :: Python :: Implementation :: PyPy",
+]
+urls.Source = "https://github.com/pypa/packaging"
+dependencies = [
+  "pyparsing>=2.0.2,!=3.0.5",
+]
+
+
+[tool.flit.sdist]
+include = ["LICENSE*", "tests/", "docs/"]
+exclude = ["docs/_build", "tests/manylinux/build-hello-world.sh", "tests/musllinux/build.sh", "tests/hello-world.c", "tests/__pycache__", "build/__pycache__"]
 
 
 [tool.mypy]
@@ -11,3 +44,8 @@ enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]
 [[tool.mypy.overrides]]
 module = ["_manylinux"]
 ignore_missing_imports = true
+
+
+[tool.isort]
+profile = "black"
+combine_as_imports = true
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index c97a4e440..000000000
--- a/setup.cfg
+++ /dev/null
@@ -1,3 +0,0 @@
-[isort]
-profile = black
-combine_as_imports = true
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 82ef248e4..000000000
--- a/setup.py
+++ /dev/null
@@ -1,69 +0,0 @@
-#!/usr/bin/env python
-# This file is dual licensed under the terms of the Apache License, Version
-# 2.0, and the BSD License. See the LICENSE file in the root of this repository
-# for complete details.
-
-import os
-import re
-
-# While I generally consider it an antipattern to try and support both
-# setuptools and distutils with a single setup.py, in this specific instance
-# where packaging is a dependency of setuptools, it can create a circular
-# dependency when projects attempt to unbundle stuff from setuptools and pip.
-# Though we don't really support that, it makes things easier if we do this and
-# should hopefully cause less issues for end users.
-try:
-    from setuptools import setup
-except ImportError:
-    from distutils.core import setup
-
-
-base_dir = os.path.dirname(__file__)
-
-about = {}
-with open(os.path.join(base_dir, "packaging", "__about__.py")) as f:
-    exec(f.read(), about)
-
-with open(os.path.join(base_dir, "README.rst")) as f:
-    long_description = f.read()
-
-with open(os.path.join(base_dir, "CHANGELOG.rst")) as f:
-    # Remove :issue:`ddd` tags that breaks the description rendering
-    changelog = re.sub(
-        r":issue:`(\d+)`",
-        r"`#\1 <https://github.com/pypa/packaging/issues/\1>`__",
-        f.read(),
-    )
-    long_description = "\n".join([long_description, changelog])
-
-
-setup(
-    name=about["__title__"],
-    version=about["__version__"],
-    description=about["__summary__"],
-    long_description=long_description,
-    long_description_content_type="text/x-rst",
-    license=about["__license__"],
-    url=about["__uri__"],
-    author=about["__author__"],
-    author_email=about["__email__"],
-    python_requires=">=3.7",
-    install_requires=["pyparsing>=2.0.2,!=3.0.5"],  # 2.0.2 + needed to avoid issue #91
-    classifiers=[
-        "Development Status :: 5 - Production/Stable",
-        "Intended Audience :: Developers",
-        "License :: OSI Approved :: Apache Software License",
-        "License :: OSI Approved :: BSD License",
-        "Programming Language :: Python",
-        "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
-        "Programming Language :: Python :: 3.9",
-        "Programming Language :: Python :: 3.10",
-        "Programming Language :: Python :: Implementation :: CPython",
-        "Programming Language :: Python :: Implementation :: PyPy",
-    ],
-    packages=["packaging"],
-    package_data={"packaging": ["py.typed"]},
-)