diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 0fed39033a43..6660d270c45a 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -82,6 +82,39 @@ jobs:
           --all \
           --verbosity=QUIET
 
+  ty:
+    name: "ty: Check stubs"
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        platform: ["linux", "win32", "darwin"]
+        # TODO: Add 3.15 once third-party runtime dependencies provide compatible wheels.
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v7
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.14"
+      - uses: astral-sh/setup-uv@v8.2.0
+        with:
+          version-file: "requirements-tests.txt"
+      - name: Install typeshed test-suite requirements
+        run: uv pip install -r requirements-tests.txt --system
+      - name: Create an isolated venv for testing
+        run: uv venv .venv
+      - name: Install third-party stub dependencies
+        run: |
+          PACKAGES=$(python tests/get_external_stub_requirements.py)
+          if [ -n "$PACKAGES" ]; then
+            uv pip install --python-version ${{ matrix.python-version }} $PACKAGES
+          fi
+          # Published stub packages can shadow the checked-in stubs when ty
+          # resolves their relative imports.
+          uv pip uninstall types-PyYAML types-pytz
+      - name: Run ty on all stubs
+        run: python tests/ty_test.py --platform=${{ matrix.platform }} --python-version=${{ matrix.python-version }} --python=.venv
+
   pyright:
     name: "pyright: Run test cases"
     runs-on: ubuntu-latest
diff --git a/requirements-tests.txt b/requirements-tests.txt
index 8ef8a20d335f..4e349ad33d0a 100644
--- a/requirements-tests.txt
+++ b/requirements-tests.txt
@@ -2,6 +2,7 @@
 # be pinned to a specific version to make failure reproducible.
 mypy==2.2.0
 pyright==1.1.411
+ty==0.0.59
 
 # Libraries used by our various scripts.
 aiohttp==3.14.1
diff --git a/stdlib/_asyncio.pyi b/stdlib/_asyncio.pyi
index 17999651f7d3..242093e1ec79 100644
--- a/stdlib/_asyncio.pyi
+++ b/stdlib/_asyncio.pyi
@@ -53,7 +53,7 @@ else:
 # since the only reason why `asyncio.Future` is invariant is the `set_result()` method,
 # and `asyncio.Task.set_result()` always raises.
 @disjoint_base
-class Task(Future[_T_co]):  # type: ignore[type-var]  # pyright: ignore[reportInvalidTypeArguments]
+class Task(Future[_T_co]):  # type: ignore[type-var]  # pyright: ignore[reportInvalidTypeArguments]  # ty:ignore[invalid-generic-class]
     if sys.version_info >= (3, 12):
         def __init__(
             self,
diff --git a/stdlib/collections/__init__.pyi b/stdlib/collections/__init__.pyi
index d9c2e342c587..39b8a3c9ab6a 100644
--- a/stdlib/collections/__init__.pyi
+++ b/stdlib/collections/__init__.pyi
@@ -364,17 +364,17 @@ class _OrderedDictValuesView(ValuesView[_VT_co]):
 # pyright doesn't have a specific error code for subclassing error!
 @final
 @type_check_only
-class _odict_keys(dict_keys[_KT_co, _VT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+class _odict_keys(dict_keys[_KT_co, _VT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[subclass-of-final-class]
     def __reversed__(self) -> Iterator[_KT_co]: ...
 
 @final
 @type_check_only
-class _odict_items(dict_items[_KT_co, _VT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+class _odict_items(dict_items[_KT_co, _VT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[subclass-of-final-class]
     def __reversed__(self) -> Iterator[tuple[_KT_co, _VT_co]]: ...
 
 @final
 @type_check_only
-class _odict_values(dict_values[_KT_co, _VT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+class _odict_values(dict_values[_KT_co, _VT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[subclass-of-final-class]
     def __reversed__(self) -> Iterator[_VT_co]: ...
 
 @disjoint_base
diff --git a/stdlib/contextlib.pyi b/stdlib/contextlib.pyi
index b95c23502a8b..dd601675265c 100644
--- a/stdlib/contextlib.pyi
+++ b/stdlib/contextlib.pyi
@@ -43,7 +43,7 @@ _CM_EF = TypeVar("_CM_EF", bound=AbstractContextManager[Any, Any] | _ExitFunc)
 # At runtime it inherits from ABC and is not a Protocol, but it is on the
 # allowlist for use as a Protocol.
 @runtime_checkable
-class AbstractContextManager(ABC, Protocol[_T_co, _ExitT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+class AbstractContextManager(ABC, Protocol[_T_co, _ExitT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[invalid-protocol]
     __slots__ = ()
     def __enter__(self) -> _T_co: ...
     @abstractmethod
@@ -55,7 +55,7 @@ class AbstractContextManager(ABC, Protocol[_T_co, _ExitT_co]):  # type: ignore[m
 # At runtime it inherits from ABC and is not a Protocol, but it is on the
 # allowlist for use as a Protocol.
 @runtime_checkable
-class AbstractAsyncContextManager(ABC, Protocol[_T_co, _ExitT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+class AbstractAsyncContextManager(ABC, Protocol[_T_co, _ExitT_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[invalid-protocol]
     __slots__ = ()
     async def __aenter__(self) -> _T_co: ...
     @abstractmethod
diff --git a/stdlib/dataclasses.pyi b/stdlib/dataclasses.pyi
index 1a7b8fd64558..fd5588e03490 100644
--- a/stdlib/dataclasses.pyi
+++ b/stdlib/dataclasses.pyi
@@ -298,7 +298,7 @@ def fields(class_or_instance: DataclassInstance | type[DataclassInstance]) -> tu
 
 # HACK: `obj: Never` typing matches if object argument is using `Any` type.
 @overload
-def is_dataclass(obj: Never) -> TypeIs[DataclassInstance | type[DataclassInstance]]: ...  # type: ignore[narrowed-type-not-subtype]  # pyright: ignore[reportGeneralTypeIssues]
+def is_dataclass(obj: Never) -> TypeIs[DataclassInstance | type[DataclassInstance]]: ...  # type: ignore[narrowed-type-not-subtype]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[invalid-type-guard-definition]
 @overload
 def is_dataclass(obj: type) -> TypeIs[type[DataclassInstance]]: ...
 @overload
@@ -308,13 +308,17 @@ class FrozenInstanceError(AttributeError): ...
 
 class InitVar(Generic[_T]):
     __slots__ = ("type",)
-    type: Type[_T]
+    type: Type[_T]  # ty:ignore[unbound-type-variable]
     def __init__(self, type: Type[_T]) -> None: ...
 
     @overload
-    def __class_getitem__(cls, type: Type[_T]) -> InitVar[_T]: ...  # pyright: ignore[reportInvalidTypeForm]
+    def __class_getitem__(
+        cls, type: Type[_T]
+    ) -> InitVar[_T]: ...  # pyright: ignore[reportInvalidTypeForm]  # ty:ignore[invalid-type-form]
     @overload
-    def __class_getitem__(cls, type: Any) -> InitVar[Any]: ...  # pyright: ignore[reportInvalidTypeForm]
+    def __class_getitem__(
+        cls, type: Any
+    ) -> InitVar[Any]: ...  # pyright: ignore[reportInvalidTypeForm]  # ty:ignore[invalid-type-form]
 
 if sys.version_info >= (3, 14):
     def make_dataclass(
diff --git a/stdlib/os/__init__.pyi b/stdlib/os/__init__.pyi
index 726e9702fb16..00c155956fb0 100644
--- a/stdlib/os/__init__.pyi
+++ b/stdlib/os/__init__.pyi
@@ -940,7 +940,7 @@ In the future, this property will contain the last metadata change time.""")
 # At runtime it inherits from ABC and is not a Protocol, but it will be
 # on the allowlist for use as a Protocol starting in 3.14.
 @runtime_checkable
-class PathLike(ABC, Protocol[AnyStr_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+class PathLike(ABC, Protocol[AnyStr_co]):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[invalid-protocol]
     __slots__ = ()
     @abstractmethod
     def __fspath__(self) -> AnyStr_co: ...
diff --git a/stdlib/platform.pyi b/stdlib/platform.pyi
index 7d837436ef79..07100d3bd592 100644
--- a/stdlib/platform.pyi
+++ b/stdlib/platform.pyi
@@ -44,7 +44,7 @@ if sys.version_info >= (3, 12):
 
         def __new__(_cls, system: str, node: str, release: str, version: str, machine: str) -> Self: ...
         @property
-        def processor(self) -> str: ...
+        def processor(self) -> str: ...  # ty:ignore[invalid-named-tuple-override]
 
 else:
     @disjoint_base
@@ -52,7 +52,7 @@ else:
         __match_args__ = ("system", "node", "release", "version", "machine")  # pyright: ignore[reportAssignmentType]
         def __new__(_cls, system: str, node: str, release: str, version: str, machine: str) -> Self: ...
         @property
-        def processor(self) -> str: ...
+        def processor(self) -> str: ...  # ty:ignore[invalid-named-tuple-override]
 
 def uname() -> uname_result: ...
 def system() -> str: ...
diff --git a/stdlib/ssl.pyi b/stdlib/ssl.pyi
index 590642d99607..8d71e4763959 100644
--- a/stdlib/ssl.pyi
+++ b/stdlib/ssl.pyi
@@ -262,8 +262,18 @@ class Purpose(_ASN1Object, enum.Enum):
     # because this is an enum, the inherited __new__ is replaced at runtime with
     # Enum.__new__.
     def __new__(cls, value: object) -> Self: ...
-    SERVER_AUTH = (129, "serverAuth", "TLS Web Server Authentication", "1.3.6.1.5.5.7.3.2")  # pyright: ignore[reportCallIssue]
-    CLIENT_AUTH = (130, "clientAuth", "TLS Web Client Authentication", "1.3.6.1.5.5.7.3.1")  # pyright: ignore[reportCallIssue]
+    SERVER_AUTH = (  # ty:ignore[invalid-assignment]
+        129,
+        "serverAuth",
+        "TLS Web Server Authentication",
+        "1.3.6.1.5.5.7.3.2",
+    )  # pyright: ignore[reportCallIssue]
+    CLIENT_AUTH = (  # ty:ignore[invalid-assignment]
+        130,
+        "clientAuth",
+        "TLS Web Client Authentication",
+        "1.3.6.1.5.5.7.3.1",
+    )  # pyright: ignore[reportCallIssue]
 
 class SSLSocket(socket.socket):
     context: SSLContext
diff --git a/stdlib/types.pyi b/stdlib/types.pyi
index 68b6b3fbe41d..328bb7552538 100644
--- a/stdlib/types.pyi
+++ b/stdlib/types.pyi
@@ -268,7 +268,7 @@ class CodeType:
         __replace__ = replace
 
 @final
-class MappingProxyType(Mapping[_KT_co, _VT_co]):  # type: ignore[type-var]  # pyright: ignore[reportInvalidTypeArguments]
+class MappingProxyType(Mapping[_KT_co, _VT_co]):  # type: ignore[type-var]  # pyright: ignore[reportInvalidTypeArguments]  # ty:ignore[invalid-generic-class]
     __hash__: ClassVar[None]  # type: ignore[assignment]
     def __new__(cls, mapping: SupportsKeysAndGetItem[_KT_co, _VT_co]) -> Self: ...
     def __getitem__(self, key: _KT_co, /) -> _VT_co: ...  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
diff --git a/stdlib/typing.pyi b/stdlib/typing.pyi
index 61439f15e785..8c1fb9d28d7c 100644
--- a/stdlib/typing.pyi
+++ b/stdlib/typing.pyi
@@ -1063,13 +1063,13 @@ class NamedTuple(tuple[Any, ...]):
 
     @final
     @classmethod
-    def _make(cls, iterable: Iterable[Any]) -> typing_extensions.Self: ...
+    def _make(cls, iterable: Iterable[Any]) -> typing_extensions.Self: ...  # ty:ignore[invalid-type-form]
     @final
     def _asdict(self) -> dict[str, Any]: ...
     @final
-    def _replace(self, **kwargs: Any) -> typing_extensions.Self: ...
+    def _replace(self, **kwargs: Any) -> typing_extensions.Self: ...  # ty:ignore[invalid-type-form]
     if sys.version_info >= (3, 13):
-        def __replace__(self, **kwargs: Any) -> typing_extensions.Self: ...
+        def __replace__(self, **kwargs: Any) -> typing_extensions.Self: ...  # ty:ignore[invalid-type-form]
 
 # Internal mypy fallback type for all typed dicts (does not exist at runtime)
 # N.B. Keep this mostly in sync with typing_extensions._TypedDict/mypy_extensions._TypedDict
diff --git a/stdlib/typing_extensions.pyi b/stdlib/typing_extensions.pyi
index 80341175e6e1..5a8848e9151d 100644
--- a/stdlib/typing_extensions.pyi
+++ b/stdlib/typing_extensions.pyi
@@ -356,9 +356,9 @@ else:
         def __init__(self, typename: str, fields: None = None, **kwargs: Any) -> None: ...
 
         @classmethod
-        def _make(cls, iterable: Iterable[Any]) -> Self: ...
+        def _make(cls, iterable: Iterable[Any]) -> Self: ...  # ty:ignore[invalid-type-form]
         def _asdict(self) -> dict[str, Any]: ...
-        def _replace(self, **kwargs: Any) -> Self: ...
+        def _replace(self, **kwargs: Any) -> Self: ...  # ty:ignore[invalid-type-form]
 
     class NewType:
         def __init__(self, name: str, tp: AnnotationForm) -> None: ...
@@ -389,7 +389,7 @@ else:
     # At runtime it inherits from ABC and is not a Protocol, but it is on the
     # allowlist for use as a Protocol.
     @runtime_checkable
-    class Buffer(Protocol, abc.ABC):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+    class Buffer(Protocol, abc.ABC):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[invalid-protocol]
         # Not actually a Protocol at runtime; see
         # https://github.com/python/typeshed/issues/10224 for why we're defining it this way
         def __buffer__(self, flags: int, /) -> memoryview: ...
diff --git a/stubs/JACK-Client/jack/__init__.pyi b/stubs/JACK-Client/jack/__init__.pyi
index 95d6e4857c2c..c173e7be07cc 100644
--- a/stubs/JACK-Client/jack/__init__.pyi
+++ b/stubs/JACK-Client/jack/__init__.pyi
@@ -12,7 +12,7 @@ from numpy.typing import NDArray
 # This is not a real subclassing. Just ensuring type-checkers sees this type as compatible with _CDataBase
 # pyright has no error code for subclassing final
 @type_check_only
-class _JackPositionT(_CDataBase):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+class _JackPositionT(_CDataBase):  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]  # ty:ignore[subclass-of-final-class]
     audio_frames_per_video_frame: float
     bar: int
     bar_start_tick: float
diff --git a/stubs/WebOb/webob/cachecontrol.pyi b/stubs/WebOb/webob/cachecontrol.pyi
index bf291dc9b494..94434539a213 100644
--- a/stubs/WebOb/webob/cachecontrol.pyi
+++ b/stubs/WebOb/webob/cachecontrol.pyi
@@ -38,7 +38,7 @@ class exists_property(Generic[_ScopeT]):
     def __delete__(self, obj: CacheControl[_ScopeT]) -> None: ...
 
 class value_property(Generic[_T, _DefaultT, _NoneLiteral, _ScopeT]):
-    def __init__(self, prop: str, default: _DefaultT = None, none: _NoneLiteral = None, type: _ScopeT = None) -> None: ...  # type: ignore[assignment]
+    def __init__(self, prop: str, default: _DefaultT = None, none: _NoneLiteral = None, type: _ScopeT = None) -> None: ...  # type: ignore[assignment]  # ty:ignore[invalid-parameter-default]
 
     @overload
     def __get__(self, obj: None, type: type[CacheControl[Any]] | None = None) -> Self: ...
diff --git a/stubs/geopandas/geopandas/geoseries.pyi b/stubs/geopandas/geopandas/geoseries.pyi
index 8e1a23f17560..b5a156cb7874 100644
--- a/stubs/geopandas/geopandas/geoseries.pyi
+++ b/stubs/geopandas/geopandas/geoseries.pyi
@@ -19,7 +19,7 @@ from .explore import _explore_geoseries
 from .io._geoarrow import GeoArrowArray
 from .plotting import plot_series
 
-class GeoSeries(GeoPandasBase, pd.Series[BaseGeometry]):  # type: ignore[type-var,misc]  # pyright: ignore[reportInvalidTypeArguments]
+class GeoSeries(GeoPandasBase, pd.Series[BaseGeometry]):  # type: ignore[type-var,misc]  # pyright: ignore[reportInvalidTypeArguments]  # ty:ignore[invalid-type-arguments]
     # Override the weird annotation of Series.__new__ in pandas-stubs
     def __new__(
         self,
diff --git a/stubs/geopandas/geopandas/plotting.pyi b/stubs/geopandas/geopandas/plotting.pyi
index b24d213f7639..e8c7c85c545c 100644
--- a/stubs/geopandas/geopandas/plotting.pyi
+++ b/stubs/geopandas/geopandas/plotting.pyi
@@ -193,7 +193,7 @@ class GeoplotAccessor(PlotAccessor):
         include_bool: bool = False,
         backend: str | None = None,
         **kwargs,
-    ) -> pd.Series[Axes]: ...  # type: ignore[type-var] # pyright: ignore[reportInvalidTypeArguments]
+    ) -> pd.Series[Axes]: ...  # type: ignore[type-var] # pyright: ignore[reportInvalidTypeArguments]  # ty:ignore[invalid-type-arguments]
     @overload
     def __call__(
         self,
diff --git a/stubs/pyogrio/pyogrio/raw.pyi b/stubs/pyogrio/pyogrio/raw.pyi
index 39a97f65a82d..cc55e91ddc1a 100644
--- a/stubs/pyogrio/pyogrio/raw.pyi
+++ b/stubs/pyogrio/pyogrio/raw.pyi
@@ -3,7 +3,7 @@ from contextlib import AbstractContextManager
 from typing import Any, Literal, TypedDict, overload, type_check_only
 
 import numpy as np
-import pyarrow as pa  # type: ignore[import-not-found]  # pyright: ignore[reportMissingImports]
+import pyarrow as pa  # type: ignore[import-not-found]  # pyright: ignore[reportMissingImports]  # ty:ignore[unresolved-import]
 import shapely as shp
 
 from ._typing import Array1D, ArrayLikeInt, ReadPathOrBuffer, SupportsArrowCStream, WritePathOrBuffer
diff --git a/stubs/python-dateutil/dateutil/tz/__init__.pyi b/stubs/python-dateutil/dateutil/tz/__init__.pyi
index 3dbbe3199855..406980bdfdab 100644
--- a/stubs/python-dateutil/dateutil/tz/__init__.pyi
+++ b/stubs/python-dateutil/dateutil/tz/__init__.pyi
@@ -1,3 +1,4 @@
+import builtins
 import sys
 from datetime import datetime
 from typing_extensions import Self
@@ -25,7 +26,7 @@ if sys.platform == "win32":
         hasdst: bool
         def __eq__(self, other: tzwinbase) -> bool: ...  # type: ignore[override]
         @staticmethod
-        def list() -> list[str]: ...
+        def list() -> builtins.list[str]: ...
         def display(self) -> str | None: ...
         def transitions(self, year: int) -> tuple[datetime, datetime] | None: ...
 
diff --git a/stubs/setuptools/setuptools/__init__.pyi b/stubs/setuptools/setuptools/__init__.pyi
index 5b2c77ab99f2..e89fce7ebdc6 100644
--- a/stubs/setuptools/setuptools/__init__.pyi
+++ b/stubs/setuptools/setuptools/__init__.pyi
@@ -155,7 +155,7 @@ def setup(
     install_requires: str | Iterable[str] = [],
     extras_require: _DictLike[Incomplete, Incomplete] = {},
     # kwargs used directly in distutils.core.setup
-    distclass: type[_DistributionT] = Distribution,  # type: ignore[assignment] # noqa: Y011
+    distclass: type[_DistributionT] = Distribution,  # type: ignore[assignment] # noqa: Y011  # ty:ignore[invalid-parameter-default]
     # Custom Distributions could accept more params
     **attrs: Any,
 ) -> _DistributionT: ...
diff --git a/stubs/yt-dlp/yt_dlp/extractor/common.pyi b/stubs/yt-dlp/yt_dlp/extractor/common.pyi
index ece237453e0a..821f045b0bf3 100644
--- a/stubs/yt-dlp/yt_dlp/extractor/common.pyi
+++ b/stubs/yt-dlp/yt_dlp/extractor/common.pyi
@@ -943,7 +943,7 @@ class InfoExtractor:
         self,
         url: str,
         *args: Unused,
-        info_dict: _InfoDict = {},  # type: ignore[typeddict-item]  # pyright: ignore[reportArgumentType]
+        info_dict: _InfoDict = {},  # type: ignore[typeddict-item]  # pyright: ignore[reportArgumentType]  # ty:ignore[missing-typed-dict-key]
         note: str = "Extracting generic embeds",
         **kwargs: Unused,
     ) -> list[dict[str, Any]]: ...
diff --git a/tests/README.md b/tests/README.md
index 6ae812cfab36..f64fe02059ee 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -3,6 +3,7 @@ This directory contains several tests:
 tests the stubs with [mypy](https://github.com/python/mypy/)
 - `tests/pyright_test.py` tests the stubs with
 [pyright](https://github.com/microsoft/pyright).
+- `tests/ty_test.py` tests the stubs with [ty](https://github.com/astral-sh/ty).
 - `tests/regr_test.py` runs mypy against the test cases for typeshed's
 stubs, guarding against accidental regressions.
 - `tests/check_typeshed_structure.py` checks that typeshed's directory
@@ -81,6 +82,22 @@ checks that would typically fail on incomplete stubs (such as `Unknown` checks).
 In typeshed's CI, pyright is run with these configuration settings on a subset of
 the stubs in typeshed (including the standard library).
 
+## ty\_test.py
+
+Run using:
+```bash
+(.venv)$ python3 tests/ty_test.py --python=.venv
+(.venv)$ python3 tests/ty_test.py stubs/PySocks --python=.venv
+```
+
+This test checks the stdlib and third-party stubs with ty, using the configuration
+in `ty.toml`. It selects the stdlib modules supported by the requested Python
+version using `stdlib/VERSIONS` and adds the third-party stub roots to ty's module
+search path. Unlike pyright, it checks `geopandas`, `seaborn`, and `shapely` on
+every target version; only the obsolete `requests` and legacy `distutils` stubs
+are excluded. Run
+`python tests/ty_test.py --help` for the supported options.
+
 ## regr\_test.py
 
 This test runs mypy against the test cases for typeshed's stdlib and third-party
diff --git a/tests/runtests.py b/tests/runtests.py
index 9da379b723a6..1ae28ea3f786 100755
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -3,6 +3,7 @@
 
 import argparse
 import json
+import os
 import re
 import subprocess
 import sys
@@ -21,6 +22,19 @@
 _FAILED = colored("Failed", "red")
 
 
+def _pythonpath_env() -> dict[str, str]:
+    pythonpath = os.environ.get("PYTHONPATH")
+    env = os.environ.copy()
+    env["PYTHONPATH"] = "lib" if not pythonpath else os.pathsep.join(("lib", pythonpath))
+    return env
+
+
+def _ty_platform() -> str:
+    if sys.platform.startswith("win"):
+        return "win32"
+    return sys.platform
+
+
 def _parse_jsonc(json_text: str) -> str:
     # strip comments from the file
     lines = [line for line in json_text.split("\n") if not line.strip().startswith("//")]
@@ -100,6 +114,23 @@ def main() -> None:
         pyright_returncode = pyright_result.returncode
         pyright_skipped = False
 
+    print(f"\nRunning ty for Python {python_version}...")
+    ty_result = subprocess.run(
+        [
+            sys.executable,
+            "tests/ty_test.py",
+            path,
+            "--python-version",
+            python_version,
+            "--platform",
+            _ty_platform(),
+            "--python",
+            sys.executable,
+        ],
+        env=_pythonpath_env(),
+        check=False,
+    )
+
     print(f"\nRunning mypy for Python {python_version}...")
     mypy_result = subprocess.run([sys.executable, "tests/mypy_test.py", path, "--python-version", python_version], check=False)
     # If mypy failed, stubtest will fail without any helpful error
@@ -171,6 +202,7 @@ def main() -> None:
             pre_commit_result.returncode,
             check_structure_result.returncode,
             pyright_returncode,
+            ty_result.returncode,
             mypy_result.returncode,
             getattr(stubtest_result, "returncode", 0),
             pyright_testcases_returncode,
@@ -197,6 +229,7 @@ def main() -> None:
         print("Pyright:", _SKIPPED)
     else:
         print("Pyright:", _SUCCESS if pyright_returncode == 0 else _FAILED)
+    print("ty:", _SUCCESS if ty_result.returncode == 0 else _FAILED)
     print("mypy:", _SUCCESS if mypy_result.returncode == 0 else _FAILED)
     if stubtest_result is None:
         print("stubtest:", _SKIPPED)
diff --git a/tests/ty_test.py b/tests/ty_test.py
new file mode 100755
index 000000000000..909a1f4d852b
--- /dev/null
+++ b/tests/ty_test.py
@@ -0,0 +1,108 @@
+#!/usr/bin/env python3
+"""Run ty on typeshed's stdlib and third-party stubs."""
+
+from __future__ import annotations
+
+import argparse
+import subprocess
+import tempfile
+from pathlib import Path
+
+from ts_utils.paths import STDLIB_PATH, STUBS_PATH, TS_BASE_PATH
+from ts_utils.utils import parse_stdlib_versions_file, supported_versions_for_module
+
+SUPPORTED_VERSIONS = ("3.10", "3.11", "3.12", "3.13", "3.14", "3.15")
+SUPPORTED_PLATFORMS = ("linux", "darwin", "win32")
+# requests is obsolete and the typed runtime package is installed instead.
+EXCLUDED_STUBS = {"requests"}
+
+
+def stdlib_files(version: str) -> list[Path]:
+    """Return the stdlib stubs available in the requested Python version."""
+    version_tuple = tuple(map(int, version.split(".")))
+    module_versions = parse_stdlib_versions_file()
+    files: list[Path] = []
+
+    for path in sorted(STDLIB_PATH.rglob("*.pyi")):
+        if "@tests" in path.parts:
+            continue
+        relative = path.relative_to(STDLIB_PATH)
+        # ty cannot resolve relative imports in the legacy distutils stubs.
+        if relative.parts[0] == "distutils":
+            continue
+        parts = list(relative.parts[:-1])
+        if relative.name != "__init__.pyi":
+            parts.append(relative.stem)
+        minimum, maximum = supported_versions_for_module(module_versions, ".".join(parts))
+        if minimum <= version_tuple <= maximum:
+            files.append(path)
+
+    return files
+
+
+def _path_files(path: Path) -> list[Path]:
+    if path.is_file():
+        return [path] if path.suffix == ".pyi" and "@tests" not in path.parts else []
+    return sorted(p for p in path.rglob("*.pyi") if "@tests" not in p.parts)
+
+
+def _filter_files(files: list[Path], paths: list[Path], root: Path) -> list[Path]:
+    selected_paths = [path if path.is_absolute() else TS_BASE_PATH / path for path in paths]
+    selected_files = {file for path in selected_paths if path.is_relative_to(root) for file in _path_files(path)}
+    return [file for file in files if file in selected_files]
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description="Typecheck typeshed's stdlib and third-party stubs with ty.")
+    parser.add_argument("paths", nargs="*", type=Path, help="Specific stdlib or third-party stubs to check")
+    parser.add_argument("--python", type=Path, help="Python interpreter or environment used to resolve third-party imports")
+    parser.add_argument("--python-version", choices=SUPPORTED_VERSIONS, default=SUPPORTED_VERSIONS[0])
+    parser.add_argument("--platform", choices=SUPPORTED_PLATFORMS, default="linux")
+    args = parser.parse_args()
+
+    third_party_files = sorted(
+        path
+        for path in STUBS_PATH.rglob("*.pyi")
+        if "@tests" not in path.parts and path.relative_to(STUBS_PATH).parts[0] not in EXCLUDED_STUBS
+    )
+    stdlib = stdlib_files(args.python_version)
+    if args.paths:
+        stdlib = _filter_files(stdlib, args.paths, STDLIB_PATH)
+        third_party_files = _filter_files(third_party_files, args.paths, STUBS_PATH)
+    files = [*stdlib, *third_party_files]
+    if not files:
+        print("No stubs to check with ty.", flush=True)
+        return 0
+    command = [
+        "ty",
+        "check",
+        "--config-file",
+        str(TS_BASE_PATH / "ty.toml"),
+        "--typeshed",
+        str(TS_BASE_PATH),
+        "--python-version",
+        args.python_version,
+        "--python-platform",
+        args.platform,
+        "--output-format",
+        "concise",
+    ]
+    if args.python is not None:
+        command.extend(("--python", str(args.python)))
+
+    for path in sorted(STUBS_PATH.iterdir()):
+        # requests is obsolete and the typed runtime package provides requests._types.
+        if path.is_dir() and path.name != "requests":
+            command.extend(("--extra-search-path", str(path)))
+    command.extend(map(str, files))
+
+    print(f"Checking {len(files)} stubs with ty ({args.python_version}, {args.platform})...", flush=True)
+    # The custom typeshed cannot also be the project root: ty would treat builtins.pyi
+    # as project source and panic while constructing its builtins model.
+    with tempfile.TemporaryDirectory() as project:
+        command[2:2] = ("--project", project)
+        return subprocess.run(command, check=False).returncode
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/ty.toml b/ty.toml
new file mode 100644
index 000000000000..36de911f6fca
--- /dev/null
+++ b/ty.toml
@@ -0,0 +1,20 @@
+[analysis]
+respect-type-ignore-comments = false
+# These imports are intentionally optional and are also ignored by mypy and pyright.
+allowed-unresolved-imports = [
+    "branca",
+    "folium",
+    "pydot",
+    "pygraphviz.**",
+    "scipy.**",
+    "twisted.**",
+    "xyzservices",
+]
+
+[rules]
+# Incompatible overrides and deprecations are inherited from the implementation
+# and are not actionable in typeshed. Keep in sync with pyrightconfig.json.
+deprecated = "ignore"
+invalid-attribute-override = "ignore"
+invalid-method-override = "ignore"
+override-of-final-method = "ignore"