diff --git a/noxfile.py b/noxfile.py
index 403a44fd..895a45fe 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -168,10 +168,21 @@ def mypy(session: Session) -> None:
 @session
 @nox.parametrize(
     "python,poetry",
-    [(python_versions[0], "1.6.1"), *((python, None) for python in python_versions)],
+    [
+        (python_versions[0], "poetry==1.6.1"),
+        (
+            python_versions[0],
+            "poetry @ git+https://github.com/radoering/poetry.git@pep621-support",
+        ),
+        *((python, None) for python in python_versions),
+    ],
 )
 def tests(session: Session, poetry: Optional[str]) -> None:
     """Run the test suite."""
+    # Install poetry first to ensure the correct version is used for 'poetry build'.
+    if poetry is not None:
+        session.run_always("python", "-m", "pip", "install", poetry, silent=True)
+
     session.install(".")
     session.install(
         "coverage[toml]",
@@ -182,10 +193,9 @@ def tests(session: Session, poetry: Optional[str]) -> None:
         "typing_extensions",
     )
 
+    # Override nox-poetry's locked Poetry version.
     if poetry is not None:
-        session.run_always(
-            "python", "-m", "pip", "install", f"poetry=={poetry}", silent=True
-        )
+        session.run_always("python", "-m", "pip", "install", poetry, silent=True)
 
     try:
         session.run("coverage", "run", "--parallel", "-m", "pytest", *session.posargs)
diff --git a/src/nox_poetry/poetry.py b/src/nox_poetry/poetry.py
index c2aae71e..98872a74 100644
--- a/src/nox_poetry/poetry.py
+++ b/src/nox_poetry/poetry.py
@@ -33,12 +33,13 @@ def __init__(self, project: Path) -> None:
         path = project / "pyproject.toml"
         text = path.read_text(encoding="utf-8")
         data: Any = tomlkit.parse(text)
-        self._config = data["tool"]["poetry"]
+        self._config = data.get("tool", {}).get("poetry", {})
+        self._pyproject = data.get("project", {})
 
     @property
     def name(self) -> str:
         """Return the package name."""
-        name = self._config["name"]
+        name = self._config.get("name", self._pyproject.get("name"))
         assert isinstance(name, str)  # noqa: S101
         return name
 
diff --git a/tests/functional/conftest.py b/tests/functional/conftest.py
index fedfee60..34d20f35 100644
--- a/tests/functional/conftest.py
+++ b/tests/functional/conftest.py
@@ -46,7 +46,9 @@ def _read_toml(self, filename: str) -> Any:
 
     def _get_config(self, key: str) -> Any:
         data: Any = self._read_toml("pyproject.toml")
-        return data["tool"]["poetry"][key]
+        poetry_config = data.get("tool", {}).get("poetry", {})
+        pyproject = data.get("project", {})
+        return poetry_config.get(key, pyproject.get(key))
 
     def get_dependency(self, name: str, data: Any = None) -> Package:
         """Return the package with the given name."""
diff --git a/tests/functional/data/pep-621/pep_621_pyproject/__init__.py b/tests/functional/data/pep-621/pep_621_pyproject/__init__.py
new file mode 100644
index 00000000..0142a443
--- /dev/null
+++ b/tests/functional/data/pep-621/pep_621_pyproject/__init__.py
@@ -0,0 +1 @@
+"""A project that uses PEP 621."""
diff --git a/tests/functional/data/pep-621/poetry.lock b/tests/functional/data/pep-621/poetry.lock
new file mode 100644
index 00000000..b35d2f04
--- /dev/null
+++ b/tests/functional/data/pep-621/poetry.lock
@@ -0,0 +1,17 @@
+# This file is automatically @generated by Poetry 1.9.0.dev0 and should not be changed by hand.
+
+[[package]]
+name = "pyflakes"
+version = "3.0.1"
+description = "passive checker of Python programs"
+optional = false
+python-versions = ">=3.6"
+files = [
+    {file = "pyflakes-3.0.1-py2.py3-none-any.whl", hash = "sha256:ec55bf7fe21fff7f1ad2f7da62363d749e2a470500eab1b555334b67aa1ef8cf"},
+    {file = "pyflakes-3.0.1.tar.gz", hash = "sha256:ec8b276a6b60bd80defed25add7e439881c19e64850afd9b346283d4165fd0fd"},
+]
+
+[metadata]
+lock-version = "2.0"
+python-versions = ">=3.7"
+content-hash = "fde4426d488839cd45ad2f892640146bbbf95d4c86183effa3ed6be3e6e5d6ae"
diff --git a/tests/functional/data/pep-621/pyproject.toml b/tests/functional/data/pep-621/pyproject.toml
new file mode 100644
index 00000000..f07d2b67
--- /dev/null
+++ b/tests/functional/data/pep-621/pyproject.toml
@@ -0,0 +1,11 @@
+[project]
+name = "pep-621-pyproject"
+version = "0.1.0"
+description = ""
+authors = [{ name = "Your Name", email = "<you@example.com>" }]
+requires-python = ">=3.7"
+dependencies = ["pyflakes>=2.1.1"]
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"
diff --git a/tests/functional/test_session.py b/tests/functional/test_session.py
index 047417e8..777a68ee 100644
--- a/tests/functional/test_session.py
+++ b/tests/functional/test_session.py
@@ -188,3 +188,24 @@ def test(session: nox_poetry.Session) -> None:
     packages = list_packages(project, test)
 
     assert set(expected) == set(packages)
+
+
+@pytest.mark.skipif(
+    Version(version("poetry")) < Version("1.9.0.dev0"),
+    reason=f"Poetry {version('poetry')} < 1.9 does not support PEP 621",
+)
+def test_pep621_pyproject_support(shared_datadir: Path) -> None:
+    """It installs packages from PEP 621 pyproject.toml."""
+    project = Project(shared_datadir / "pep-621")
+
+    @nox_poetry.session
+    def test(session: nox_poetry.Session) -> None:
+        """Install the dependencies."""
+        session.install(".")
+
+    run_nox_with_noxfile(project, [test], [nox_poetry])
+
+    expected = [project.package, *project.locked_packages]
+    packages = list_packages(project, test)
+
+    assert set(expected) == set(packages)