@@ -103,10 +103,10 @@ commands:
       - run:
           name: Install Python dependencies
           command: |
-            python -m pip install --user -r requirements/dev/build-requirements.txt
+            python -m pip install --user --group build
             python -m pip install --user \
                 numpy<< parameters.numpy_version >> \
-                -r requirements/doc/doc-requirements.txt
+                --group doc
             python -m pip install --no-deps --user \
                 git+https://github.com/matplotlib/mpl-sphinx-theme.git
 
 
@@ -143,7 +143,7 @@ jobs:
         uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4.3.0
         with:
           path: C:\cygwin\home\runneradmin\.cache\pip
-          key: Cygwin-py3.${{ matrix.python-minor-version }}-pip-${{ hashFiles('requirements/*/*.txt') }}
+          key: Cygwin-py3.${{ matrix.python-minor-version }}-pip-${{ hashFiles('pyproject.toml') }}
           restore-keys: ${{ matrix.os }}-py3.${{ matrix.python-minor-version }}-pip-
 
       - name: Cache ccache
@@ -174,15 +174,9 @@ jobs:
       - name: Install Python dependencies
         shell: bash.exe -eo pipefail -o igncr "{0}"
         run: |
-          python -m pip install --upgrade pip setuptools wheel
-          python -m pip install kiwisolver 'numpy>=1.22,<1.26' pillow importlib_resources
-          grep -v -F -e psutil requirements/testing/all.txt >requirements_test.txt
-          python -m pip install meson-python pybind11
+          python -m pip install --group build 'numpy>=1.25,<1.26'
           export PATH="/usr/local/bin:$PATH"
-          python -m pip install --no-build-isolation 'contourpy>=1.0.1'
-          python -m pip install --upgrade cycler fonttools \
-              packaging pyparsing python-dateutil setuptools-scm \
-              -r requirements_test.txt sphinx ipython
+          python -m pip install --upgrade --group test sphinx ipython
           python -m pip install --upgrade pycairo 'cairocffi>=0.8' PyGObject &&
              python -c 'import gi; gi.require_version("Gtk", "3.0"); from gi.repository import Gtk' &&
              echo 'PyGObject is available' ||
 
@@ -66,7 +66,7 @@ jobs:
           python-version: '3.11'
 
       - name: Install mypy
-        run: pip3 install -r requirements/testing/mypy.txt -r requirements/testing/all.txt
+        run: pip3 install --group build --group typing
 
       - name: Set up reviewdog
         uses: reviewdog/action-setup@d8edfce3dd5e1ec6978745e801f9c50b5ef80252  # v1.4.0
 
@@ -50,14 +50,14 @@ jobs:
           - name-suffix: "(Minimum Versions)"
             os: ubuntu-22.04
             python-version: '3.11'
-            extra-requirements: '-c requirements/testing/minver.txt'
+            extra-requirements: '--group test-minver'
             delete-font-cache: true
             # https://github.com/matplotlib/matplotlib/issues/29844
             pygobject-ver: '<3.52.0'
           - os: ubuntu-22.04
             python-version: '3.11'
             CFLAGS: "-fno-lto"  # Ensure that disabling LTO works.
-            extra-requirements: '-r requirements/testing/extra.txt'
+            extra-requirements: '--group test-extra'
             # https://github.com/matplotlib/matplotlib/issues/29844
             pygobject-ver: '<3.52.0'
           - name-suffix: "(Extra TeX packages)"
@@ -182,15 +182,15 @@ jobs:
         if: startsWith(runner.os, 'Linux')
         with:
           path: ~/.cache/pip
-          key: ${{ matrix.os }}-py${{ matrix.python-version }}-pip-${{ hashFiles('requirements/*/*.txt') }}
+          key: ${{ matrix.os }}-py${{ matrix.python-version }}-pip-${{ hashFiles('pyproject.toml') }}
           restore-keys: |
             ${{ matrix.os }}-py${{ matrix.python-version }}-pip-
       - name: Cache pip
         uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830  # v4.3.0
         if: startsWith(runner.os, 'macOS')
         with:
           path: ~/Library/Caches/pip
-          key: ${{ matrix.os }}-py${{ matrix.python-version }}-pip-${{ hashFiles('requirements/*/*.txt') }}
+          key: ${{ matrix.os }}-py${{ matrix.python-version }}-pip-${{ hashFiles('pyproject.toml') }}
           restore-keys: |
             ${{ matrix.os }}-py${{ matrix.python-version }}-pip-
       - name: Cache ccache
@@ -227,12 +227,8 @@ jobs:
 
           # Install dependencies from PyPI.
           # Preinstall build requirements to enable no-build-isolation builds.
-          python -m pip install --upgrade $PRE \
-            'contourpy>=1.0.1' cycler fonttools kiwisolver importlib_resources \
-            packaging pillow 'pyparsing!=3.1.0' python-dateutil setuptools-scm \
-            'meson-python>=0.13.1' 'pybind11>=2.13.2' \
-            -r requirements/testing/all.txt \
-            ${{ matrix.extra-requirements }}
+          python -m pip install --upgrade $PRE --prefer-binary \
+            --group build --group test ${{ matrix.extra-requirements }}
 
           # Install optional dependencies from PyPI.
           # Sphinx is needed to run sphinxext tests
 
@@ -74,8 +74,8 @@ stages:
 
           - bash: |
               python -m pip install --upgrade pip
-              python -m pip install --upgrade -r requirements/dev/build-requirements.txt
-              python -m pip install -r requirements/testing/all.txt -r requirements/testing/extra.txt
+              python -m pip install --upgrade --group build
+              python -m pip install --prefer-binary --group test --group test-extra
             displayName: 'Install dependencies with pip'
 
           - bash: |
 
@@ -0,0 +1,11 @@
+pip 25.1 suggested for development
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Dependencies for development (build and testing) are now specified as `Dependency Groups
+<https://packaging.python.org/en/latest/specifications/dependency-groups/#dependency-groups>`_
+instead of `individual requirements files
+<https://pip.pypa.io/en/stable/reference/requirements-file-format/>`_.
+
+Consequently, a version of pip that supports Dependency Groups is suggested, namely
+version 25.1 or higher. Note that if you install build/testing dependencies manually (by
+copying the list from ``pyproject.toml``), then an older version of pip is sufficient.
@@ -177,7 +177,8 @@ setup.
 
       Install the Python dependencies with ::
 
-        pip install -r requirements/dev/dev-requirements.txt
+        pip install -U pip  # You may skip this step if pip 25.1 is already available.
+        pip install --group dev
 
       Remember to activate the environment whenever you start working on Matplotlib!
 
@@ -270,7 +271,7 @@ Install Matplotlib in editable mode
 Install Matplotlib in editable mode from the :file:`matplotlib` directory using the
 command ::
 
-    python -m pip install --verbose --no-build-isolation --editable ".[dev]"
+    python -m pip install --verbose --no-build-isolation --group dev --editable .
 
 The 'editable/develop mode' builds everything and places links in your Python environment
 so that Python will be able to import Matplotlib from your development source directory.
 
@@ -439,7 +439,7 @@ To build the documentation you must have the tagged version installed, but
 build the docs from the ``ver-doc`` branch.  An easy way to arrange this is::
 
   pip install matplotlib
-  pip install -r requirements/doc/doc-requirements.txt
+  pip install --group doc
   git checkout v3.7.0-doc
   git clean -xfd
   make -Cdoc O="-t release -j$(nproc)" html latexpdf LATEXMKOPTS="-silent -f"
 
@@ -396,17 +396,11 @@ Documentation dependencies
 Python
 ------
 
-The additional Python packages required to build the
-:ref:`documentation <documenting-matplotlib>` are listed in
-:file:`doc-requirements.txt` and can be installed using ::
-
-    pip install -r requirements/doc/doc-requirements.txt
-
-The content of :file:`doc-requirements.txt` is also shown below:
-
-.. include:: ../../requirements/doc/doc-requirements.txt
-   :literal:
+The additional Python packages required to build the :ref:`documentation
+<documenting-matplotlib>` are listed in :file:`pyproject.toml` and can be
+installed using ::
 
+    pip install --group doc
 
 .. _doc-dependencies-external:
 
 
@@ -2,7 +2,7 @@
 #
 #   conda env create -f environment.yml
 #   conda activate mpl-dev
-#   pip install --verbose --no-build-isolation --editable ".[dev]"
+#   pip install --verbose --no-build-isolation --group dev --editable .
 #
 ---
 name: mpl-dev
Original file line number	Diff line number	Diff line change
@@ -2,7 +2,7 @@
2	2	#
3	3	# conda env create -f environment.yml
4	4	# conda activate mpl-dev
5		- # pip install --verbose --no-build-isolation --editable ".[dev]"
	5	+ # pip install --verbose --no-build-isolation --group dev --editable .
6	6	#
7	7	---
8	8	name: mpl-dev