diff --git a/.gitignore b/.gitignore
index df4d06b..34f3844 100644
--- a/.gitignore
+++ b/.gitignore
@@ -75,3 +75,6 @@ tcl
 /.tox/
 /.ruff_cache/
 .env
+
+# Lock files from uv, pixi, pipenv, etc.
+*.lock
diff --git a/MANIFEST.in b/MANIFEST.in
index 0f19707..524b815 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -9,7 +9,6 @@ include *.toml
 include *.yml
 include *.rst
 include *.png
-include setup.*
 include configure*
 include requirements*
 include .dockerignore
diff --git a/configure b/configure
index 6d317d4..f815b0e 100755
--- a/configure
+++ b/configure
@@ -29,7 +29,7 @@ CLI_ARGS=$1
 
 # Requirement arguments passed to pip and used by default or with --dev.
 REQUIREMENTS="--editable . --constraint requirements.txt"
-DEV_REQUIREMENTS="--editable .[dev] --constraint requirements.txt --constraint requirements-dev.txt"
+DEV_REQUIREMENTS="--editable . --group dev --constraint requirements.txt --constraint requirements-dev.txt"
 
 # where we create a virtualenv
 VIRTUALENV_DIR=venv
diff --git a/configure.bat b/configure.bat
index 15ab701..9a7ac64 100755
--- a/configure.bat
+++ b/configure.bat
@@ -27,7 +27,7 @@
 
 @rem # Requirement arguments passed to pip and used by default or with --dev.
 set "REQUIREMENTS=--editable . --constraint requirements.txt"
-set "DEV_REQUIREMENTS=--editable .[dev] --constraint requirements.txt --constraint requirements-dev.txt"
+set "DEV_REQUIREMENTS=--editable . --group dev --constraint requirements.txt --constraint requirements-dev.txt"
 
 @rem # where we create a virtualenv
 set "VIRTUALENV_DIR=venv"
diff --git a/etc/scripts/README.rst b/etc/scripts/README.rst
index 5e54a2c..e2eb491 100755
--- a/etc/scripts/README.rst
+++ b/etc/scripts/README.rst
@@ -72,8 +72,7 @@ gen_requirements_dev.py** --help for details.
 Note: this does NOT hash requirements for now.
 
 Note: Be aware that if you are using "conditional" requirements (e.g. only for
-OS or Python versions) in setup.py/setp.cfg/requirements.txt as these are NOT
-yet supported.
+OS or Python versions) in pyproject.toml as these are NOT yet supported.
 
 
 Populate a thirdparty directory with wheels, sources, .ABOUT and license files
diff --git a/pyproject.toml b/pyproject.toml
index f106e69..2dfd19a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,84 @@
 [build-system]
-requires = ["setuptools >= 50", "wheel"]
+requires = [
+    "setuptools >= 77",
+]
 build-backend = "setuptools.build_meta"
 
+[project]
+name = "license-expression"
+authors = [
+    {name = "nexB. Inc. and others", email = "info@aboutcode.org"},
+]
+description = "comprehensive utility library to parse, compare, simplify and normalize license expressions (such as SPDX license expressions) using boolean logic"
+readme = "README.rst"
+keywords = [
+    "open source",
+    "license expression",
+    "license",
+    "spdx",
+    "boolean",
+    "parse expression",
+    "normalize expression",
+    "compare expression",
+    "licence",
+]
+license = "Apache-2.0"
+license-files = [
+    "apache-2.0.LICENSE",
+    "NOTICE",
+    "AUTHORS.rst",
+    "CHANGELOG.rst",
+    "CODE_OF_CONDUCT.rst",
+    "README.rst",
+]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Intended Audience :: Developers",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3 :: Only",
+    "Topic :: Software Development",
+    "Topic :: Utilities",
+]
+requires-python = ">=3.10"
+dependencies = [
+    "boolean.py >= 4.0",
+]
+version = "30.4.4"
+
+[project.urls]
+Homepage = "https://github.com/aboutcode-org/license-expression"
+
+[dependency-groups]
+tests = [
+    "pytest >= 7.0.1",
+    "pytest-xdist >= 2",
+]
+lint = [
+    "twine",
+    "ruff",
+]
+docs = [
+    # do not use this as this triggers a bug
+    # in setuptools_scm:aboutcode-toolkit >= 6.0.0
+    "doc8>=0.11.2",
+    "Sphinx>=5.0.2",
+    "sphinx-rtd-theme>=1.0.0",
+    "sphinxcontrib-apidoc >= 0.4.0",
+    "sphinx-reredirects >= 0.1.2",
+    "sphinx-autobuild",
+    "sphinx-rtd-dark-mode>=1.3.0",
+    "sphinx-copybutton",
+]
+
+dev = [
+    {include-group = "tests"},
+    {include-group = "lint"},
+    {include-group = "docs"},
+]
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
 [tool.setuptools_scm]
 # this is used populated when creating a git archive
 # and when there is .git dir and/or there is no git installed
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 3989bc2..0000000
--- a/setup.cfg
+++ /dev/null
@@ -1,74 +0,0 @@
-[metadata]
-name = license-expression
-version = 30.4.4
-license = Apache-2.0
-
-# description must be on ONE line https://github.com/pypa/setuptools/issues/1390
-description = license-expression is a comprehensive utility library to parse, compare, simplify and normalize license expressions (such as SPDX license expressions) using boolean logic.
-long_description = file:README.rst
-long_description_content_type = text/x-rst
-url = https://github.com/aboutcode-org/license-expression
-
-author = nexB. Inc. and others
-author_email = info@aboutcode.org
-
-classifiers =
-    Development Status :: 5 - Production/Stable
-    Intended Audience :: Developers
-    Programming Language :: Python :: 3
-    Programming Language :: Python :: 3 :: Only
-    Topic :: Software Development
-    Topic :: Utilities
-
-keywords =
-    open source
-    license expression
-    license
-    spdx
-    boolean
-    parse expression
-    normalize expression
-    compare expression
-    licence
-
-license_files =
-    apache-2.0.LICENSE
-    NOTICE
-    AUTHORS.rst
-    CHANGELOG.rst
-    CODE_OF_CONDUCT.rst
-    README.rst
-
-[options]
-python_requires = >=3.10
-
-package_dir =
-    =src
-packages = find:
-include_package_data = true
-zip_safe = false
-
-install_requires =
-    boolean.py >= 4.0
-
-
-[options.packages.find]
-where = src
-
-
-[options.extras_require]
-dev =
-    pytest >= 7.0.1
-    pytest-xdist >= 2
-    # do not use this as this triggers a bug
-    # in setuptools_scm:aboutcode-toolkit >= 6.0.0
-    twine
-    ruff
-    Sphinx>=5.0.2
-    sphinx-rtd-theme>=1.0.0
-    sphinxcontrib-apidoc >= 0.4.0
-    sphinx-reredirects >= 0.1.2
-    doc8>=0.11.2
-    sphinx-autobuild
-    sphinx-rtd-dark-mode>=1.3.0
-    sphinx-copybutton
diff --git a/setup.py b/setup.py
deleted file mode 100644
index bac24a4..0000000
--- a/setup.py
+++ /dev/null
@@ -1,6 +0,0 @@
-#!/usr/bin/env python
-
-import setuptools
-
-if __name__ == "__main__":
-    setuptools.setup()