diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 7e89cab5..0068bdf9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -68,11 +68,6 @@ jobs:
           - norun
           # Playwright test
           - ui
-        include:
-          # The earliest actions/setup-python versions depend on the runner.
-          - ubuntu_version: "22.04"
-            python_version: "3.9"
-            repo_type: venv
 
     steps:
       - uses: actions/checkout@v4
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 7bb04d17..c0e4658d 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -11,7 +11,7 @@ sphinx:
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.10"
+    python: "3.11"
 
 python:
   install:
diff --git a/repo2docker/app.py b/repo2docker/app.py
index b9684c11..538b3730 100755
--- a/repo2docker/app.py
+++ b/repo2docker/app.py
@@ -33,6 +33,7 @@
     LegacyBinderDockerBuildPack,
     NixBuildPack,
     PipfileBuildPack,
+    PyprojectBuildPack,
     PythonBuildPack,
     RBuildPack,
 )
@@ -100,6 +101,7 @@ def _default_log_level(self):
             RBuildPack,
             CondaBuildPack,
             PipfileBuildPack,
+            PyprojectBuildPack,
             PythonBuildPack,
         ],
         config=True,
diff --git a/repo2docker/buildpacks/__init__.py b/repo2docker/buildpacks/__init__.py
index 7568000b..21a512a8 100644
--- a/repo2docker/buildpacks/__init__.py
+++ b/repo2docker/buildpacks/__init__.py
@@ -5,5 +5,6 @@
 from .legacy import LegacyBinderDockerBuildPack
 from .nix import NixBuildPack
 from .pipfile import PipfileBuildPack
+from .pyproject import PyprojectBuildPack
 from .python import PythonBuildPack
 from .r import RBuildPack
diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
new file mode 100644
index 00000000..a952c8af
--- /dev/null
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -0,0 +1,147 @@
+"""Buildpack for Git repositories with pyproject.toml
+
+Support to pyproject.toml was added to pip v10.0,
+see https://pip.pypa.io/en/latest/reference/build-system/pyproject-toml/.
+"""
+
+import os
+import re
+import tomllib
+from functools import lru_cache
+
+from ..conda import CondaBuildPack
+
+VERSION_PAT = re.compile(r"\d+(\.\d+)*")
+
+
+class PyprojectBuildPack(CondaBuildPack):
+    """Setup Python with pyproject.toml for use with a repository."""
+
+    @property
+    def python_version(self):
+        """
+        Detect the Python version declared in a `pyproject.toml`.
+        Will return 'x.y' if version is found (e.g '3.6'),
+        or a Falsy empty string '' if not found.
+        """
+
+        if hasattr(self, "_python_version"):
+            return self._python_version
+
+        try:
+            with open(self.binder_path("runtime.txt")) as f:
+                runtime = f.read().strip()
+        except FileNotFoundError:
+            runtime = ""
+
+        if runtime.startswith("python-"):
+            runtime_python_version = runtime.split("-", 1)[1]
+        else:
+            # not a Python runtime (e.g. R, which subclasses this)
+            # use the default Python
+            runtime_python_version = self.major_pythons["3"]
+            self.log.warning(
+                f"Python version unspecified in runtime.txt, using current default Python version {runtime_python_version}. This will change in the future."
+            )
+
+        runtime_python_version_info = runtime_python_version.split(".")
+        if len(runtime_python_version_info) == 1:
+            runtime_python_version = self.major_pythons[runtime_python_version_info[0]]
+            runtime_python_version_info = runtime_python_version.split(".")
+
+        pyproject_file = self.binder_path("pyproject.toml")
+        with open(pyproject_file, "rb") as _pyproject_file:
+            pyproject_toml = tomllib.load(_pyproject_file)
+
+        if "project" in pyproject_toml:
+            if "requires-python" in pyproject_toml["project"]:
+                # This is the minumum version!
+                raw_pyproject_minimum_version = pyproject_toml["project"][
+                    "requires-python"
+                ]
+
+                match = VERSION_PAT.match(raw_pyproject_minimum_version)
+                if match:
+                    pyproject_minimum_version = match.group()
+                    pyproject_minimum_version_info = pyproject_minimum_version.split(
+                        "."
+                    )
+
+                    if (
+                        runtime_python_version_info[0]
+                        < pyproject_minimum_version_info[0]
+                    ) or (
+                        runtime_python_version_info[1]
+                        < pyproject_minimum_version_info[1]
+                    ):
+                        raise RuntimeError(
+                            "runtime.txt version not supported by pyproject.toml."
+                        )
+
+        self._python_version = runtime_python_version
+        return self._python_version
+
+    @lru_cache
+    def get_preassemble_script_files(self):
+        """Return files needed for preassembly"""
+        files = super().get_preassemble_script_files()
+        path = self.binder_path("pyproject.toml")
+        if os.path.exists(path):
+            files[path] = path
+        return files
+
+    @lru_cache
+    def get_preassemble_scripts(self):
+        """scripts to run prior to staging the repo contents"""
+        scripts = super().get_preassemble_scripts()
+        return scripts
+
+    @lru_cache
+    def get_assemble_scripts(self):
+        """Return series of build-steps specific to this repository."""
+        # If we have pyproject.toml declare the
+        # use of Python 2, Python 2.7 will be made available in the *kernel*
+        # environment. The notebook servers environment on the other hand
+        # requires Python 3 but may require something additional installed in it
+        # still such as `nbgitpuller`. For this purpose, a "requirements3.txt"
+        # file will be used to install dependencies for the notebook servers
+        # environment, if Python 2 had been specified for the kernel
+        # environment.
+        assemble_scripts = super().get_assemble_scripts()
+
+        if self.separate_kernel_env:
+            # using legacy Python (e.g. 2.7) as a kernel
+
+            # requirements3.txt allows for packages to be installed to the
+            # notebook servers Python environment
+            nb_requirements_file = self.binder_path("requirements3.txt")
+            if os.path.exists(nb_requirements_file):
+                assemble_scripts.append(
+                    (
+                        "${NB_USER}",
+                        f'${{NB_PYTHON_PREFIX}}/bin/pip install --no-cache-dir -r "{nb_requirements_file}"',
+                    )
+                )
+
+        assemble_scripts.append(
+            (
+                "${NB_USER}",
+                "${KERNEL_PYTHON_PREFIX}/bin/pip install --no-cache-dir --editable .",
+            )
+        )
+
+        return assemble_scripts
+
+    def detect(self):
+        """Check if current repo should be built with the pyproject.toml buildpack."""
+        # first make sure python is not explicitly unwanted
+        runtime_txt = self.binder_path("runtime.txt")
+        if os.path.exists(runtime_txt):
+            with open(runtime_txt) as f:
+                runtime = f.read().strip()
+            if not runtime.startswith("python-"):
+                return False
+
+        pyproject_file = self.binder_path("pyproject.toml")
+
+        return os.path.exists(pyproject_file)
diff --git a/setup.py b/setup.py
index c8fcbbd7..577254ed 100644
--- a/setup.py
+++ b/setup.py
@@ -62,7 +62,7 @@ def get_identifier(json):
         "toml",
         "traitlets",
     ],
-    python_requires=">=3.9",
+    python_requires=">=3.11",
     author="Project Jupyter Contributors",
     author_email="jupyter@googlegroups.com",
     url="https://repo2docker.readthedocs.io/en/latest/",