diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 586fed3..9db890b 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -25,7 +25,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install tox tox-gh-actions poetry==1.2.2
+        pip install 'tox<5' tox-gh-actions 'poetry<1.5'
     - name: Test with tox
       run: tox
 
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 20a407e..d16d054 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,6 +1,12 @@
 Changelog
 =========
 
+0.16.5 (2023-03-01)
+-------------------
+
+- Don't flag ``TypedDict`` from ``typing_extensions`` in Python versions
+  where ``typing`` has ``TypedDict`` itself.
+
 0.16.4 (2023-01-13)
 -------------------
 
diff --git a/docs/advanced.rst b/docs/advanced.rst
index 865288b..80a6213 100644
--- a/docs/advanced.rst
+++ b/docs/advanced.rst
@@ -18,7 +18,7 @@ Use the following configuration:
 
    repos:
    - repo: https://github.com/ariebovenberg/slotscheck
-     rev: v0.16.4
+     rev: v0.16.5
      hooks:
      - id: slotscheck
        # If your Python files are not importable from the project root,
diff --git a/poetry.lock b/poetry.lock
index 41c9008..b3affe6 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry and should not be changed by hand.
+# This file is automatically @generated by Poetry 1.4.0 and should not be changed by hand.
 
 [[package]]
 name = "attrs"
@@ -100,63 +100,63 @@ files = [
 
 [[package]]
 name = "coverage"
-version = "7.0.5"
+version = "7.2.1"
 description = "Code coverage measurement for Python"
 category = "dev"
 optional = false
 python-versions = ">=3.7"
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+    {file = "coverage-7.2.1-cp38-cp38-musllinux_1_1_i686.whl", hash = "sha256:8dca3c1706670297851bca1acff9618455122246bdae623be31eca744ade05ec"},
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+    {file = "coverage-7.2.1-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:8a6450da4c7afc4534305b2b7d8650131e130610cea448ff240b6ab73d7eab63"},
+    {file = "coverage-7.2.1-cp39-cp39-musllinux_1_1_aarch64.whl", hash = "sha256:99f4dd81b2bb8fc67c3da68b1f5ee1650aca06faa585cbc6818dbf67893c6d58"},
+    {file = "coverage-7.2.1-cp39-cp39-musllinux_1_1_i686.whl", hash = "sha256:bdd3f2f285ddcf2e75174248b2406189261a79e7fedee2ceeadc76219b6faa0e"},
+    {file = "coverage-7.2.1-cp39-cp39-musllinux_1_1_x86_64.whl", hash = "sha256:f29351393eb05e6326f044a7b45ed8e38cb4dcc38570d12791f271399dc41431"},
+    {file = "coverage-7.2.1-cp39-cp39-win32.whl", hash = "sha256:e2b50ebc2b6121edf352336d503357321b9d8738bb7a72d06fc56153fd3f4cd8"},
+    {file = "coverage-7.2.1-cp39-cp39-win_amd64.whl", hash = "sha256:bd5a12239c0006252244f94863f1c518ac256160cd316ea5c47fb1a11b25889a"},
+    {file = "coverage-7.2.1-pp37.pp38.pp39-none-any.whl", hash = "sha256:436313d129db7cf5b4ac355dd2bd3f7c7e5294af077b090b85de75f8458b8616"},
+    {file = "coverage-7.2.1.tar.gz", hash = "sha256:c77f2a9093ccf329dd523a9b2b3c854c20d2a3d968b6def3b820272ca6732242"},
 ]
 
 [package.dependencies]
@@ -165,18 +165,6 @@ tomli = {version = "*", optional = true, markers = "python_full_version <= \"3.1
 [package.extras]
 toml = ["tomli"]
 
-[[package]]
-name = "distlib"
-version = "0.3.6"
-description = "Distribution utilities"
-category = "dev"
-optional = false
-python-versions = "*"
-files = [
-    {file = "distlib-0.3.6-py2.py3-none-any.whl", hash = "sha256:f35c4b692542ca110de7ef0bea44d73981caeb34ca0b9b6b2e6d7790dda8f80e"},
-    {file = "distlib-0.3.6.tar.gz", hash = "sha256:14bad2d9b04d3a36127ac97f30b12a19268f211063d8f8ee4f47108896e11b46"},
-]
-
 [[package]]
 name = "exceptiongroup"
 version = "1.1.0"
@@ -192,22 +180,6 @@ files = [
 [package.extras]
 test = ["pytest (>=6)"]
 
-[[package]]
-name = "filelock"
-version = "3.9.0"
-description = "A platform independent file lock."
-category = "dev"
-optional = false
-python-versions = ">=3.7"
-files = [
-    {file = "filelock-3.9.0-py3-none-any.whl", hash = "sha256:f58d535af89bb9ad5cd4df046f741f8553a418c01a7856bf0d173bbc9f6bd16d"},
-    {file = "filelock-3.9.0.tar.gz", hash = "sha256:7b319f24340b51f55a2bf7a12ac0755a9b03e718311dac567a0f4f7fabd2f5de"},
-]
-
-[package.extras]
-docs = ["furo (>=2022.12.7)", "sphinx (>=5.3)", "sphinx-autodoc-typehints (>=1.19.5)"]
-testing = ["covdefaults (>=2.2.2)", "coverage (>=7.0.1)", "pytest (>=7.2)", "pytest-cov (>=4)", "pytest-timeout (>=2.1)"]
-
 [[package]]
 name = "flake8"
 version = "5.0.4"
@@ -338,14 +310,14 @@ reports = ["lxml"]
 
 [[package]]
 name = "mypy-extensions"
-version = "0.4.3"
-description = "Experimental type system extensions for programs checked with the mypy typechecker."
+version = "1.0.0"
+description = "Type system extensions for programs checked with the mypy type checker."
 category = "dev"
 optional = false
-python-versions = "*"
+python-versions = ">=3.5"
 files = [
-    {file = "mypy_extensions-0.4.3-py2.py3-none-any.whl", hash = "sha256:090fedd75945a69ae91ce1303b5824f428daf5a028d2f6ab8a299250a846f15d"},
-    {file = "mypy_extensions-0.4.3.tar.gz", hash = "sha256:2d82818f5bb3e369420cb3c4060a7970edba416647068eb4c5343488a6c604a8"},
+    {file = "mypy_extensions-1.0.0-py3-none-any.whl", hash = "sha256:4392f6c0eb8a5668a69e23d168ffa70f0be9ccfd32b5cc2d26a34ae5b844552d"},
+    {file = "mypy_extensions-1.0.0.tar.gz", hash = "sha256:75dbf8955dc00442a438fc4d0666508a9a97b6bd41aa2f0ffe9d2f2725af0782"},
 ]
 
 [[package]]
@@ -362,34 +334,34 @@ files = [
 
 [[package]]
 name = "pathspec"
-version = "0.10.3"
+version = "0.11.0"
 description = "Utility library for gitignore style pattern matching of file paths."
 category = "dev"
 optional = false
 python-versions = ">=3.7"
 files = [
-    {file = "pathspec-0.10.3-py3-none-any.whl", hash = "sha256:3c95343af8b756205e2aba76e843ba9520a24dd84f68c22b9f93251507509dd6"},
-    {file = "pathspec-0.10.3.tar.gz", hash = "sha256:56200de4077d9d0791465aa9095a01d421861e405b5096955051deefd697d6f6"},
+    {file = "pathspec-0.11.0-py3-none-any.whl", hash = "sha256:3a66eb970cbac598f9e5ccb5b2cf58930cd8e3ed86d393d541eaf2d8b1705229"},
+    {file = "pathspec-0.11.0.tar.gz", hash = "sha256:64d338d4e0914e91c1792321e6907b5a593f1ab1851de7fc269557a21b30ebbc"},
 ]
 
 [[package]]
 name = "platformdirs"
-version = "2.6.2"
+version = "3.0.0"
 description = "A small Python package for determining appropriate platform-specific dirs, e.g. a \"user data dir\"."
 category = "dev"
 optional = false
 python-versions = ">=3.7"
 files = [
-    {file = "platformdirs-2.6.2-py3-none-any.whl", hash = "sha256:83c8f6d04389165de7c9b6f0c682439697887bca0aa2f1c87ef1826be3584490"},
-    {file = "platformdirs-2.6.2.tar.gz", hash = "sha256:e1fea1fe471b9ff8332e229df3cb7de4f53eeea4998d3b6bfff542115e998bd2"},
+    {file = "platformdirs-3.0.0-py3-none-any.whl", hash = "sha256:b1d5eb14f221506f50d6604a561f4c5786d9e80355219694a1b244bcd96f4567"},
+    {file = "platformdirs-3.0.0.tar.gz", hash = "sha256:8a1228abb1ef82d788f74139988b137e78692984ec7b08eaa6c65f1723af28f9"},
 ]
 
 [package.dependencies]
 typing-extensions = {version = ">=4.4", markers = "python_version < \"3.8\""}
 
 [package.extras]
-docs = ["furo (>=2022.12.7)", "proselint (>=0.13)", "sphinx (>=5.3)", "sphinx-autodoc-typehints (>=1.19.5)"]
-test = ["appdirs (==1.4.4)", "covdefaults (>=2.2.2)", "pytest (>=7.2)", "pytest-cov (>=4)", "pytest-mock (>=3.10)"]
+docs = ["furo (>=2022.12.7)", "proselint (>=0.13)", "sphinx (>=6.1.3)", "sphinx-autodoc-typehints (>=1.22,!=1.23.4)"]
+test = ["appdirs (==1.4.4)", "covdefaults (>=2.2.2)", "pytest (>=7.2.1)", "pytest-cov (>=4)", "pytest-mock (>=3.10)"]
 
 [[package]]
 name = "pluggy"
@@ -410,18 +382,6 @@ importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 dev = ["pre-commit", "tox"]
 testing = ["pytest", "pytest-benchmark"]
 
-[[package]]
-name = "py"
-version = "1.11.0"
-description = "library with cross-python path, ini-parsing, io, code, log facilities"
-category = "dev"
-optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
-files = [
-    {file = "py-1.11.0-py2.py3-none-any.whl", hash = "sha256:607c53218732647dff4acdfcd50cb62615cedf612e72d1724fb1a0cc6405b378"},
-    {file = "py-1.11.0.tar.gz", hash = "sha256:51c75c4126074b472f746a24399ad32f6053d1b34b68d2fa41e558e6f4a98719"},
-]
-
 [[package]]
 name = "pycodestyle"
 version = "2.9.1"
@@ -560,18 +520,6 @@ pytest = ">=5.0"
 [package.extras]
 dev = ["pre-commit", "pytest-asyncio", "tox"]
 
-[[package]]
-name = "six"
-version = "1.16.0"
-description = "Python 2 and 3 compatibility utilities"
-category = "dev"
-optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*"
-files = [
-    {file = "six-1.16.0-py2.py3-none-any.whl", hash = "sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254"},
-    {file = "six-1.16.0.tar.gz", hash = "sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926"},
-]
-
 [[package]]
 name = "tomli"
 version = "2.0.1"
@@ -584,33 +532,6 @@ files = [
     {file = "tomli-2.0.1.tar.gz", hash = "sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f"},
 ]
 
-[[package]]
-name = "tox"
-version = "3.28.0"
-description = "tox is a generic virtualenv management and test command line tool"
-category = "dev"
-optional = false
-python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
-files = [
-    {file = "tox-3.28.0-py2.py3-none-any.whl", hash = "sha256:57b5ab7e8bb3074edc3c0c0b4b192a4f3799d3723b2c5b76f1fa9f2d40316eea"},
-    {file = "tox-3.28.0.tar.gz", hash = "sha256:d0d28f3fe6d6d7195c27f8b054c3e99d5451952b54abdae673b71609a581f640"},
-]
-
-[package.dependencies]
-colorama = {version = ">=0.4.1", markers = "platform_system == \"Windows\""}
-filelock = ">=3.0.0"
-importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
-packaging = ">=14"
-pluggy = ">=0.12.0"
-py = ">=1.4.17"
-six = ">=1.14.0"
-tomli = {version = ">=2.0.1", markers = "python_version >= \"3.7\" and python_version < \"3.11\""}
-virtualenv = ">=16.0.0,<20.0.0 || >20.0.0,<20.0.1 || >20.0.1,<20.0.2 || >20.0.2,<20.0.3 || >20.0.3,<20.0.4 || >20.0.4,<20.0.5 || >20.0.5,<20.0.6 || >20.0.6,<20.0.7 || >20.0.7"
-
-[package.extras]
-docs = ["pygments-github-lexers (>=0.0.5)", "sphinx (>=2.0.0)", "sphinxcontrib-autoprogram (>=0.1.5)", "towncrier (>=18.5.0)"]
-testing = ["flaky (>=3.4.0)", "freezegun (>=0.3.11)", "pathlib2 (>=2.3.3)", "psutil (>=5.6.1)", "pytest (>=4.0.0)", "pytest-cov (>=2.5.1)", "pytest-mock (>=1.10.0)", "pytest-randomly (>=1.0.0)"]
-
 [[package]]
 name = "typed-ast"
 version = "1.5.4"
@@ -645,18 +566,6 @@ files = [
     {file = "typed_ast-1.5.4.tar.gz", hash = "sha256:39e21ceb7388e4bb37f4c679d72707ed46c2fbf2a5609b8b8ebc4b067d977df2"},
 ]
 
-[[package]]
-name = "types-dataclasses"
-version = "0.6.6"
-description = "Typing stubs for dataclasses"
-category = "dev"
-optional = false
-python-versions = "*"
-files = [
-    {file = "types-dataclasses-0.6.6.tar.gz", hash = "sha256:4b5a2fcf8e568d5a1974cd69010e320e1af8251177ec968de7b9bb49aa49f7b9"},
-    {file = "types_dataclasses-0.6.6-py3-none-any.whl", hash = "sha256:a0a1ab5324ba30363a15c9daa0f053ae4fff914812a1ebd8ad84a08e5349574d"},
-]
-
 [[package]]
 name = "typing-extensions"
 version = "4.5.0"
@@ -669,45 +578,23 @@ files = [
     {file = "typing_extensions-4.5.0.tar.gz", hash = "sha256:5cb5f4a79139d699607b3ef622a1dedafa84e115ab0024e0d9c044a9479ca7cb"},
 ]
 
-[[package]]
-name = "virtualenv"
-version = "20.16.2"
-description = "Virtual Python Environment builder"
-category = "dev"
-optional = false
-python-versions = ">=3.6"
-files = [
-    {file = "virtualenv-20.16.2-py2.py3-none-any.whl", hash = "sha256:635b272a8e2f77cb051946f46c60a54ace3cb5e25568228bd6b57fc70eca9ff3"},
-    {file = "virtualenv-20.16.2.tar.gz", hash = "sha256:0ef5be6d07181946891f5abc8047fda8bc2f0b4b9bf222c64e6e8963baee76db"},
-]
-
-[package.dependencies]
-distlib = ">=0.3.1,<1"
-filelock = ">=3.2,<4"
-importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
-platformdirs = ">=2,<3"
-
-[package.extras]
-docs = ["proselint (>=0.10.2)", "sphinx (>=3)", "sphinx-argparse (>=0.2.5)", "sphinx-rtd-theme (>=0.4.3)", "towncrier (>=21.3)"]
-testing = ["coverage (>=4)", "coverage-enable-subprocess (>=1)", "flaky (>=3)", "packaging (>=20.0)", "pytest (>=4)", "pytest-env (>=0.6.2)", "pytest-freezegun (>=0.4.1)", "pytest-mock (>=2)", "pytest-randomly (>=1)", "pytest-timeout (>=1)"]
-
 [[package]]
 name = "zipp"
-version = "3.11.0"
+version = "3.15.0"
 description = "Backport of pathlib-compatible object wrapper for zip files"
 category = "main"
 optional = false
 python-versions = ">=3.7"
 files = [
-    {file = "zipp-3.11.0-py3-none-any.whl", hash = "sha256:83a28fcb75844b5c0cdaf5aa4003c2d728c77e05f5aeabe8e95e56727005fbaa"},
-    {file = "zipp-3.11.0.tar.gz", hash = "sha256:a7a22e05929290a67401440b39690ae6563279bced5f314609d9d03798f56766"},
+    {file = "zipp-3.15.0-py3-none-any.whl", hash = "sha256:48904fc76a60e542af151aded95726c1a5c34ed43ab4134b597665c86d7ad556"},
+    {file = "zipp-3.15.0.tar.gz", hash = "sha256:112929ad649da941c23de50f356a2b5570c954b65150642bccdd66bf194d224b"},
 ]
 
 [package.extras]
-docs = ["furo", "jaraco.packaging (>=9)", "jaraco.tidelift (>=1.4)", "rst.linker (>=1.9)", "sphinx (>=3.5)"]
-testing = ["flake8 (<5)", "func-timeout", "jaraco.functools", "jaraco.itertools", "more-itertools", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=1.3)", "pytest-flake8", "pytest-mypy (>=0.9.1)"]
+docs = ["furo", "jaraco.packaging (>=9)", "jaraco.tidelift (>=1.4)", "rst.linker (>=1.9)", "sphinx (>=3.5)", "sphinx-lint"]
+testing = ["big-O", "flake8 (<5)", "jaraco.functools", "jaraco.itertools", "more-itertools", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=1.3)", "pytest-flake8", "pytest-mypy (>=0.9.1)"]
 
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.7,<4"
-content-hash = "9671b19a3bd4f543fe2b1d60cf639eaf01227928701debbc8229988152d07a8a"
+content-hash = "133e5e346bc4405f1944929c45075c5f49a77940fa0b4adf348d28809b11e985"
diff --git a/pyproject.toml b/pyproject.toml
index 64d58ee..133a98e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "slotscheck"
-version = "0.16.4"
+version = "0.16.5"
 description = "Ensure your __slots__ are working properly."
 authors = ["Arie Bovenberg <a.c.bovenberg@gmail.com>"]
 license = "MIT"
@@ -34,12 +34,11 @@ flake8 = "^5.0.4"
 isort = "^5.11.5"
 mypy = "^1.0"
 pytest = "^7.2.1"
-tox = "^3.27.1"
 black = "^23.1"
 pytest-cov = "^4.0.0"
 pytest-mock = "^3.6.1"
-types-dataclasses = "^0.6.6"
-# Not actually used, but a rare library whose __init__ is an extension.
+typing_extensions = ">=4.1,<5"
+# Only actually needed as an example library whose __init__ is an extension.
 pydantic = "1.9.2"
 
 [tool.poetry.scripts]
diff --git a/src/slotscheck/checks.py b/src/slotscheck/checks.py
index ace6a04..ef2a013 100644
--- a/src/slotscheck/checks.py
+++ b/src/slotscheck/checks.py
@@ -1,12 +1,23 @@
 "Slots-related checks and inspection tools"
 import platform
 import sys
-from typing import Collection, Iterator, Optional
+from typing import Callable, Collection, Iterator, Optional
+
+from .common import either
+
+is_typeddict: Callable[[type], bool]
 
 try:
     from typing import is_typeddict
-except ImportError:  # pragma: no cover
-    from typing_extensions import is_typeddict
+
+    try:
+        from typing_extensions import is_typeddict as _is_typing_ext_typeddict
+    except ModuleNotFoundError:
+        pass
+    else:
+        is_typeddict = either(is_typeddict, _is_typing_ext_typeddict)
+except ModuleNotFoundError:  # pragma: no cover
+    from typing_extensions import is_typeddict as is_any_typeddict
 
 
 def slots(c: type) -> Optional[Collection[str]]:
@@ -26,7 +37,7 @@ def has_slots(c: type) -> bool:
     return (
         "__slots__" in c.__dict__
         or not (issubclass(c, BaseException) or is_pure_python(c))
-        or is_typeddict(c)
+        or is_any_typeddict(c)
     )
 
 
diff --git a/src/slotscheck/common.py b/src/slotscheck/common.py
index 1cdd441..62f6e6d 100644
--- a/src/slotscheck/common.py
+++ b/src/slotscheck/common.py
@@ -12,6 +12,7 @@
     Set,
     Tuple,
     TypeVar,
+    overload,
 )
 
 flatten = chain.from_iterable
@@ -69,6 +70,22 @@ def both(__a: Predicate[_T1], __b: Predicate[_T1]) -> Predicate[_T1]:
     return lambda x: __a(x) and __b(x)
 
 
+@overload
+def either(
+    __a: Callable[[_T1], bool], __b: Callable[[_T1], bool]
+) -> Callable[[_T1], bool]:
+    ...
+
+
+@overload
+def either(__a: Predicate[_T1], __b: Predicate[_T1]) -> Predicate[_T1]:
+    ...
+
+
+def either(__a: Any, __b: Any) -> Any:
+    return lambda x: __a(x) or __b(x)
+
+
 def map_optional(
     f: Callable[[_T1], Optional[_T2]], it: Iterable[_T1]
 ) -> Iterator[_T2]:
diff --git a/tests/src/test_checks.py b/tests/src/test_checks.py
index 98fa52c..ac30fa1 100644
--- a/tests/src/test_checks.py
+++ b/tests/src/test_checks.py
@@ -7,13 +7,14 @@
 from xml.etree.ElementTree import Element
 
 import pytest
+from typing_extensions import TypedDict as TypingExtensionsTypedDict
 
 from slotscheck.checks import has_slotless_base, has_slots, slots_overlap
 
 try:
     from typing import TypedDict
 except ImportError:
-    from typing_extensions import TypedDict
+    TypedDict = TypingExtensionsTypedDict
 
 
 class HasSlots:
@@ -73,6 +74,10 @@ class MyDict(TypedDict):
     foo: str
 
 
+class MyTypingExtensionsTypedDict(TypingExtensionsTypedDict):
+    bla: int
+
+
 class TestHasSlots:
     @pytest.mark.parametrize(
         "klass",
@@ -84,6 +89,9 @@ def test_not_purepython(self, klass):
     def test_typeddict(self):
         assert has_slots(MyDict)
 
+    def test_typing_extensions_typeddict(self):
+        assert has_slots(MyTypingExtensionsTypedDict)
+
     @pytest.mark.parametrize(
         "klass",
         [