diff --git a/pkg_resources/__init__.py b/pkg_resources/__init__.py
index 76aa5e77bac..85d0645403a 100644
--- a/pkg_resources/__init__.py
+++ b/pkg_resources/__init__.py
@@ -568,24 +568,30 @@ def get_entry_info(dist: _EPDistType, group: str, name: str) -> EntryPoint | Non
 class IMetadataProvider(Protocol):
     def has_metadata(self, name: str) -> bool:
         """Does the package's distribution contain the named metadata?"""
+        ...
 
     def get_metadata(self, name: str) -> str:
         """The named metadata resource as a string"""
+        ...
 
     def get_metadata_lines(self, name: str) -> Iterator[str]:
         """Yield named metadata resource as list of non-blank non-comment lines
 
         Leading and trailing whitespace is stripped from each line, and lines
         with ``#`` as the first non-blank character are omitted."""
+        ...
 
     def metadata_isdir(self, name: str) -> bool:
         """Is the named metadata a directory?  (like ``os.path.isdir()``)"""
+        ...
 
     def metadata_listdir(self, name: str) -> list[str]:
         """List of metadata names in the directory (like ``os.listdir()``)"""
+        ...
 
     def run_script(self, script_name: str, namespace: dict[str, Any]) -> None:
         """Execute the named script in the supplied namespace dictionary"""
+        ...
 
 
 class IResourceProvider(IMetadataProvider, Protocol):
@@ -597,6 +603,7 @@ def get_resource_filename(
         """Return a true filesystem path for `resource_name`
 
         `manager` must be a ``ResourceManager``"""
+        ...
 
     def get_resource_stream(
         self, manager: ResourceManager, resource_name: str
@@ -604,6 +611,7 @@ def get_resource_stream(
         """Return a readable file-like object for `resource_name`
 
         `manager` must be a ``ResourceManager``"""
+        ...
 
     def get_resource_string(
         self, manager: ResourceManager, resource_name: str
@@ -611,15 +619,19 @@ def get_resource_string(
         """Return the contents of `resource_name` as :obj:`bytes`
 
         `manager` must be a ``ResourceManager``"""
+        ...
 
     def has_resource(self, resource_name: str) -> bool:
         """Does the package contain the named resource?"""
+        ...
 
     def resource_isdir(self, resource_name: str) -> bool:
         """Is the named resource a directory?  (like ``os.path.isdir()``)"""
+        ...
 
     def resource_listdir(self, resource_name: str) -> list[str]:
         """List of resource names in the directory (like ``os.listdir()``)"""
+        ...
 
 
 class WorkingSet:
diff --git a/pkg_resources/tests/test_pkg_resources.py b/pkg_resources/tests/test_pkg_resources.py
index 023adf60b0c..18adb3c9d22 100644
--- a/pkg_resources/tests/test_pkg_resources.py
+++ b/pkg_resources/tests/test_pkg_resources.py
@@ -70,7 +70,7 @@ def teardown_class(cls):
             finalizer()
 
     def test_resource_listdir(self):
-        import mod
+        import mod  # pyright: ignore[reportMissingImports] # Temporary package for test
 
         zp = pkg_resources.ZipProvider(mod)
 
@@ -84,7 +84,7 @@ def test_resource_listdir(self):
         assert zp.resource_listdir('nonexistent') == []
         assert zp.resource_listdir('nonexistent/') == []
 
-        import mod2
+        import mod2  # pyright: ignore[reportMissingImports] # Temporary package for test
 
         zp2 = pkg_resources.ZipProvider(mod2)
 
@@ -100,7 +100,7 @@ def test_resource_filename_rewrites_on_change(self):
         same size and modification time, it should not be overwritten on a
         subsequent call to get_resource_filename.
         """
-        import mod
+        import mod  # pyright: ignore[reportMissingImports] # Temporary package for test
 
         manager = pkg_resources.ResourceManager()
         zp = pkg_resources.ZipProvider(mod)
diff --git a/pkg_resources/tests/test_resources.py b/pkg_resources/tests/test_resources.py
index 3b672969528..f5e793fb90a 100644
--- a/pkg_resources/tests/test_resources.py
+++ b/pkg_resources/tests/test_resources.py
@@ -817,11 +817,11 @@ def test_two_levels_deep(self, symlinked_tmpdir):
             (pkg1 / '__init__.py').write_text(self.ns_str, encoding='utf-8')
             (pkg2 / '__init__.py').write_text(self.ns_str, encoding='utf-8')
         with pytest.warns(DeprecationWarning, match="pkg_resources.declare_namespace"):
-            import pkg1
+            import pkg1  # pyright: ignore[reportMissingImports] # Temporary package for test
         assert "pkg1" in pkg_resources._namespace_packages
         # attempt to import pkg2 from site-pkgs2
         with pytest.warns(DeprecationWarning, match="pkg_resources.declare_namespace"):
-            import pkg1.pkg2
+            import pkg1.pkg2  # pyright: ignore[reportMissingImports] # Temporary package for test
         # check the _namespace_packages dict
         assert "pkg1.pkg2" in pkg_resources._namespace_packages
         assert pkg_resources._namespace_packages["pkg1"] == ["pkg1.pkg2"]
@@ -862,8 +862,8 @@ def test_path_order(self, symlinked_tmpdir):
             (subpkg / '__init__.py').write_text(vers_str % number, encoding='utf-8')
 
         with pytest.warns(DeprecationWarning, match="pkg_resources.declare_namespace"):
-            import nspkg
-            import nspkg.subpkg
+            import nspkg  # pyright: ignore[reportMissingImports] # Temporary package for test
+            import nspkg.subpkg  # pyright: ignore[reportMissingImports] # Temporary package for test
         expected = [str(site.realpath() / 'nspkg') for site in site_dirs]
         assert nspkg.__path__ == expected
         assert nspkg.subpkg.__version__ == 1
diff --git a/pyproject.toml b/pyproject.toml
index bae68252e4d..ce78b204e1e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ test = [
 
 	# local
 	"virtualenv>=13.0.0",
-	"wheel>=0.44.0",  # Consistent requirement normalisation in METADATA (see #4547)
+	"wheel>=0.44.0", # Consistent requirement normalisation in METADATA (see #4547)
 	"pip>=19.1", # For proper file:// URLs support.
 	"packaging>=23.2",
 	"jaraco.envs>=2.2",
@@ -52,11 +52,12 @@ test = [
 	"pytest-timeout",
 	'pytest-perf; sys_platform != "cygwin"', # workaround for jaraco/inflect#195, pydantic/pydantic-core#773 (see #3986)
 	# for tools/finalize.py
-	'jaraco.develop >= 7.21; python_version >= "3.9" and sys_platform != "cygwin"',
+	'jaraco.develop >= 7.21; sys_platform != "cygwin"',
 	"pytest-home >= 0.5",
-	# pin mypy version so a new version doesn't suddenly cause the CI to fail,
+	# pin type-checkers so a new version doesn't suddenly cause the CI to fail,
 	# until types-setuptools is removed from typeshed.
-	# For help with static-typing issues, or mypy update, ping @Avasam 
+	# For help with static-typing issues, or mypy/pyright update, ping @Avasam
+	"pyright == 1.1.377",
 	"mypy==1.11.*",
 	# No Python 3.11 dependencies require tomli, but needed for type-checking since we import it directly
 	"tomli",
diff --git a/pyrightconfig.json b/pyrightconfig.json
new file mode 100644
index 00000000000..cd04c33371e
--- /dev/null
+++ b/pyrightconfig.json
@@ -0,0 +1,32 @@
+{
+	"$schema": "https://raw.githubusercontent.com/microsoft/pyright/main/packages/vscode-pyright/schemas/pyrightconfig.schema.json",
+	"exclude": [
+		"build",
+		".tox",
+		".eggs",
+		"**/_vendor", // Vendored
+		"setuptools/_distutils", // Vendored
+		"setuptools/config/_validate_pyproject/**", // Auto-generated
+	],
+	// Our testing setup doesn't allow passing CLI arguments, so local devs have to set this manually.
+	// "pythonVersion": "3.8",
+	// For now we don't mind if mypy's `type: ignore` comments accidentally suppresses pyright issues
+	"enableTypeIgnoreComments": true,
+	"typeCheckingMode": "basic",
+	// Too many issues caused by dynamic patching, still worth fixing when we can
+	"reportAttributeAccessIssue": "warning",
+	// Fails on Python 3.12 due to missing distutils and on cygwin CI tests
+	"reportAssignmentType": "warning",
+	"reportMissingImports": "warning",
+	"reportOptionalCall": "warning",
+	// FIXME: A handful of reportOperatorIssue spread throughout the codebase
+	"reportOperatorIssue": "warning",
+	// Deferred initialization (initialize_options/finalize_options) causes many "potentially None" issues
+	// TODO: Fix with type-guards or by changing how it's initialized
+	"reportArgumentType": "warning", // A lot of these are caused by jaraco.path.build's spec argument not being a Mapping https://github.com/jaraco/jaraco.path/pull/3
+	"reportCallIssue": "warning",
+	"reportGeneralTypeIssues": "warning",
+	"reportOptionalIterable": "warning",
+	"reportOptionalMemberAccess": "warning",
+	"reportOptionalOperand": "warning",
+}
diff --git a/setuptools/__init__.py b/setuptools/__init__.py
index 1d3156ff107..29267b6c1fe 100644
--- a/setuptools/__init__.py
+++ b/setuptools/__init__.py
@@ -7,6 +7,7 @@
 import re
 import sys
 from abc import abstractmethod
+from collections.abc import Mapping
 from typing import TYPE_CHECKING, TypeVar, overload
 
 sys.path.extend(((vendor_path := os.path.join(os.path.dirname(os.path.dirname(__file__)), 'setuptools', '_vendor')) not in sys.path) * [vendor_path])  # fmt: skip
@@ -54,7 +55,7 @@ class MinimalDistribution(distutils.core.Distribution):
         fetch_build_eggs interface.
         """
 
-        def __init__(self, attrs):
+        def __init__(self, attrs: Mapping[str, object]):
             _incl = 'dependency_links', 'setup_requires'
             filtered = {k: attrs[k] for k in set(_incl) & set(attrs)}
             super().__init__(filtered)
@@ -114,8 +115,10 @@ def setup(**attrs):
 setup.__doc__ = distutils.core.setup.__doc__
 
 if TYPE_CHECKING:
+    from typing_extensions import TypeAlias
+
     # Work around a mypy issue where type[T] can't be used as a base: https://github.com/python/mypy/issues/10962
-    _Command = distutils.core.Command
+    _Command: TypeAlias = distutils.core.Command
 else:
     _Command = monkey.get_unpatched(distutils.core.Command)
 
diff --git a/setuptools/_reqs.py b/setuptools/_reqs.py
index 2d09244b430..71ea23dea9f 100644
--- a/setuptools/_reqs.py
+++ b/setuptools/_reqs.py
@@ -28,15 +28,13 @@ def parse_strings(strs: _StrOrIter) -> Iterator[str]:
     return text.join_continuation(map(text.drop_comment, text.yield_lines(strs)))
 
 
+# These overloads are only needed because of a mypy false-positive, pyright gets it right
+# https://github.com/python/mypy/issues/3737
 @overload
 def parse(strs: _StrOrIter) -> Iterator[Requirement]: ...
-
-
 @overload
 def parse(strs: _StrOrIter, parser: Callable[[str], _T]) -> Iterator[_T]: ...
-
-
-def parse(strs, parser=parse_req):
+def parse(strs: _StrOrIter, parser: Callable[[str], _T] = parse_req) -> Iterator[_T]:  # type: ignore[assignment]
     """
     Replacement for ``pkg_resources.parse_requirements`` that uses ``packaging``.
     """
diff --git a/setuptools/command/build.py b/setuptools/command/build.py
index 0c5e544804f..f60fcbda154 100644
--- a/setuptools/command/build.py
+++ b/setuptools/command/build.py
@@ -87,12 +87,15 @@ def finalize_options(self):
 
     def initialize_options(self):
         """(Required by the original :class:`setuptools.Command` interface)"""
+        ...
 
     def finalize_options(self):
         """(Required by the original :class:`setuptools.Command` interface)"""
+        ...
 
     def run(self):
         """(Required by the original :class:`setuptools.Command` interface)"""
+        ...
 
     def get_source_files(self) -> list[str]:
         """
@@ -104,6 +107,7 @@ def get_source_files(self) -> list[str]:
         with all the files necessary to build the distribution.
         All files should be strings relative to the project root directory.
         """
+        ...
 
     def get_outputs(self) -> list[str]:
         """
@@ -117,6 +121,7 @@ def get_outputs(self) -> list[str]:
            in ``get_output_mapping()`` plus files that are generated during the build
            and don't correspond to any source file already present in the project.
         """
+        ...
 
     def get_output_mapping(self) -> dict[str, str]:
         """
@@ -127,3 +132,4 @@ def get_output_mapping(self) -> dict[str, str]:
         Destination files should be strings in the form of
         ``"{build_lib}/destination/file/path"``.
         """
+        ...
diff --git a/setuptools/command/build_clib.py b/setuptools/command/build_clib.py
index 9db57ac8a20..d532762ebe1 100644
--- a/setuptools/command/build_clib.py
+++ b/setuptools/command/build_clib.py
@@ -5,7 +5,9 @@
 from distutils.errors import DistutilsSetupError
 
 try:
-    from distutils._modified import newer_pairwise_group
+    from distutils._modified import (  # pyright: ignore[reportMissingImports]
+        newer_pairwise_group,
+    )
 except ImportError:
     # fallback for SETUPTOOLS_USE_DISTUTILS=stdlib
     from .._distutils._modified import newer_pairwise_group
diff --git a/setuptools/command/build_ext.py b/setuptools/command/build_ext.py
index 51c1771a338..1bb48eb9fa7 100644
--- a/setuptools/command/build_ext.py
+++ b/setuptools/command/build_ext.py
@@ -156,20 +156,18 @@ def _get_output_mapping(self) -> Iterator[tuple[str, str]]:
                 yield (output_cache, inplace_cache)
 
     def get_ext_filename(self, fullname):
-        so_ext = os.getenv('SETUPTOOLS_EXT_SUFFIX')
+        so_ext = os.getenv('SETUPTOOLS_EXT_SUFFIX', '')
         if so_ext:
             filename = os.path.join(*fullname.split('.')) + so_ext
         else:
             filename = _build_ext.get_ext_filename(self, fullname)
-            so_ext = get_config_var('EXT_SUFFIX')
+            so_ext = str(get_config_var('EXT_SUFFIX'))
 
         if fullname in self.ext_map:
             ext = self.ext_map[fullname]
-            use_abi3 = ext.py_limited_api and get_abi3_suffix()
-            if use_abi3:
-                filename = filename[: -len(so_ext)]
-                so_ext = get_abi3_suffix()
-                filename = filename + so_ext
+            abi3_suffix = get_abi3_suffix()
+            if ext.py_limited_api and abi3_suffix:  # Use abi3
+                filename = filename[: -len(so_ext)] + abi3_suffix
             if isinstance(ext, Library):
                 fn, ext = os.path.splitext(filename)
                 return self.shlib_compiler.library_filename(fn, libtype)
diff --git a/setuptools/command/easy_install.py b/setuptools/command/easy_install.py
index 54d1e48449e..46c0a231eb1 100644
--- a/setuptools/command/easy_install.py
+++ b/setuptools/command/easy_install.py
@@ -1792,7 +1792,7 @@ def auto_chmod(func, arg, exc):
         return func(arg)
     et, ev, _ = sys.exc_info()
     # TODO: This code doesn't make sense. What is it trying to do?
-    raise (ev[0], ev[1] + (" %s %s" % (func, arg)))
+    raise (ev[0], ev[1] + (" %s %s" % (func, arg)))  # pyright: ignore[reportOptionalSubscript, reportIndexIssue]
 
 
 def update_dist_caches(dist_path, fix_zipimporter_caches):
@@ -2018,7 +2018,9 @@ def is_python_script(script_text, filename):
 
 
 try:
-    from os import chmod as _chmod
+    from os import (
+        chmod as _chmod,  # pyright: ignore[reportAssignmentType] # Loosing type-safety w/ pyright, but that's ok
+    )
 except ImportError:
     # Jython compatibility
     def _chmod(*args: object, **kwargs: object) -> None:  # type: ignore[misc] # Mypy re-uses the imported definition anyway
diff --git a/setuptools/command/editable_wheel.py b/setuptools/command/editable_wheel.py
index 46852c1a948..9eaa62aba0f 100644
--- a/setuptools/command/editable_wheel.py
+++ b/setuptools/command/editable_wheel.py
@@ -39,6 +39,8 @@
 from .install_scripts import install_scripts as install_scripts_cls
 
 if TYPE_CHECKING:
+    from typing_extensions import Self
+
     from .._vendor.wheel.wheelfile import WheelFile
 
 _P = TypeVar("_P", bound=StrPath)
@@ -379,7 +381,7 @@ def _select_strategy(
 class EditableStrategy(Protocol):
     def __call__(self, wheel: WheelFile, files: list[str], mapping: dict[str, str]): ...
 
-    def __enter__(self): ...
+    def __enter__(self) -> Self: ...
 
     def __exit__(self, _exc_type, _exc_value, _traceback): ...
 
diff --git a/setuptools/config/_apply_pyprojecttoml.py b/setuptools/config/_apply_pyprojecttoml.py
index 7b9c0b1a594..da1a900c7e7 100644
--- a/setuptools/config/_apply_pyprojecttoml.py
+++ b/setuptools/config/_apply_pyprojecttoml.py
@@ -16,7 +16,7 @@
 from functools import partial, reduce
 from inspect import cleandoc
 from itertools import chain
-from types import MappingProxyType
+from types import MappingProxyType, ModuleType
 from typing import TYPE_CHECKING, Any, Callable, Dict, Mapping, Union
 
 from .._path import StrPath
@@ -275,7 +275,7 @@ def _valid_command_options(cmdclass: Mapping = EMPTY) -> dict[str, set[str]]:
     return valid_options
 
 
-def _load_ep(ep: metadata.EntryPoint) -> tuple[str, type] | None:
+def _load_ep(ep: metadata.EntryPoint) -> tuple[str, ModuleType] | None:
     if ep.value.startswith("wheel.bdist_wheel"):
         # Ignore deprecated entrypoint from wheel and avoid warning pypa/wheel#631
         # TODO: remove check when `bdist_wheel` has been fully removed from pypa/wheel
diff --git a/setuptools/config/pyprojecttoml.py b/setuptools/config/pyprojecttoml.py
index 943b9f5a00a..a381e38eae7 100644
--- a/setuptools/config/pyprojecttoml.py
+++ b/setuptools/config/pyprojecttoml.py
@@ -303,7 +303,10 @@ def _obtain(self, dist: Distribution, field: str, package_dir: Mapping[str, str]
     def _obtain_version(self, dist: Distribution, package_dir: Mapping[str, str]):
         # Since plugins can set version, let's silently skip if it cannot be obtained
         if "version" in self.dynamic and "version" in self.dynamic_cfg:
-            return _expand.version(self._obtain(dist, "version", package_dir))
+            return _expand.version(
+                # We already do an early check for the presence of "version"
+                self._obtain(dist, "version", package_dir)  # pyright: ignore[reportArgumentType]
+            )
         return None
 
     def _obtain_readme(self, dist: Distribution) -> dict[str, str] | None:
@@ -313,9 +316,10 @@ def _obtain_readme(self, dist: Distribution) -> dict[str, str] | None:
         dynamic_cfg = self.dynamic_cfg
         if "readme" in dynamic_cfg:
             return {
+                # We already do an early check for the presence of "readme"
                 "text": self._obtain(dist, "readme", {}),
                 "content-type": dynamic_cfg["readme"].get("content-type", "text/x-rst"),
-            }
+            }  # pyright: ignore[reportReturnType]
 
         self._ensure_previously_set(dist, "readme")
         return None
diff --git a/setuptools/monkey.py b/setuptools/monkey.py
index abcc2755be0..a69ccd3312c 100644
--- a/setuptools/monkey.py
+++ b/setuptools/monkey.py
@@ -10,11 +10,13 @@
 import sys
 import types
 from importlib import import_module
-from typing import TypeVar
+from typing import Type, TypeVar, cast, overload
 
 import distutils.filelist
 
 _T = TypeVar("_T")
+_UnpatchT = TypeVar("_UnpatchT", type, types.FunctionType)
+
 
 __all__: list[str] = []
 """
@@ -37,25 +39,30 @@ def _get_mro(cls):
     return inspect.getmro(cls)
 
 
-def get_unpatched(item: _T) -> _T:
-    lookup = (
-        get_unpatched_class
-        if isinstance(item, type)
-        else get_unpatched_function
-        if isinstance(item, types.FunctionType)
-        else lambda item: None
-    )
-    return lookup(item)
+@overload
+def get_unpatched(item: _UnpatchT) -> _UnpatchT: ...
+@overload
+def get_unpatched(item: object) -> None: ...
+def get_unpatched(
+    item: type | types.FunctionType | object,
+) -> type | types.FunctionType | None:
+    if isinstance(item, type):
+        return get_unpatched_class(item)
+    if isinstance(item, types.FunctionType):
+        return get_unpatched_function(item)
+    return None
 
 
-def get_unpatched_class(cls):
+def get_unpatched_class(cls: type[_T]) -> type[_T]:
     """Protect against re-patching the distutils if reloaded
 
     Also ensures that no other distutils extension monkeypatched the distutils
     first.
     """
     external_bases = (
-        cls for cls in _get_mro(cls) if not cls.__module__.startswith('setuptools')
+        cast(Type[_T], cls)
+        for cls in _get_mro(cls)
+        if not cls.__module__.startswith('setuptools')
     )
     base = next(external_bases)
     if not base.__module__.startswith('distutils'):
diff --git a/setuptools/package_index.py b/setuptools/package_index.py
index a66cbb2e613..71c34704d41 100644
--- a/setuptools/package_index.py
+++ b/setuptools/package_index.py
@@ -1072,7 +1072,7 @@ def open_with_auth(url, opener=urllib.request.urlopen):
     if scheme in ('http', 'https'):
         auth, address = _splituser(netloc)
     else:
-        auth = None
+        auth, address = (None, None)
 
     if not auth:
         cred = PyPIConfig().find_credential(url)
diff --git a/setuptools/sandbox.py b/setuptools/sandbox.py
index 7d545f1004c..98bd26ab9e5 100644
--- a/setuptools/sandbox.py
+++ b/setuptools/sandbox.py
@@ -18,7 +18,7 @@
 from distutils.errors import DistutilsError
 
 if sys.platform.startswith('java'):
-    import org.python.modules.posix.PosixModule as _os
+    import org.python.modules.posix.PosixModule as _os  # pyright: ignore[reportMissingImports]
 else:
     _os = sys.modules[os.name]
 _open = open
diff --git a/setuptools/tests/test_config_discovery.py b/setuptools/tests/test_config_discovery.py
index af172953e33..6b60c7e7f7a 100644
--- a/setuptools/tests/test_config_discovery.py
+++ b/setuptools/tests/test_config_discovery.py
@@ -2,6 +2,7 @@
 import sys
 from configparser import ConfigParser
 from itertools import product
+from typing import cast
 
 import jaraco.path
 import pytest
@@ -618,7 +619,10 @@ def _get_dist(dist_path, attrs):
     script = dist_path / 'setup.py'
     if script.exists():
         with Path(dist_path):
-            dist = distutils.core.run_setup("setup.py", {}, stop_after="init")
+            dist = cast(
+                Distribution,
+                distutils.core.run_setup("setup.py", {}, stop_after="init"),
+            )
     else:
         dist = Distribution(attrs)
 
diff --git a/setuptools/tests/test_setuptools.py b/setuptools/tests/test_setuptools.py
index 6af1d98c6b6..72b8ed47f11 100644
--- a/setuptools/tests/test_setuptools.py
+++ b/setuptools/tests/test_setuptools.py
@@ -53,7 +53,7 @@ def testExtractConst(self):
         def f1():
             global x, y, z
             x = "test"
-            y = z
+            y = z  # pyright: ignore[reportUnboundVariable] # Explicitly testing for this runtime issue
 
         fc = f1.__code__
 
diff --git a/tox.ini b/tox.ini
index cbade4ff462..ef4185e3d79 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,6 +6,7 @@ setenv =
 	PYTHONWARNDEFAULTENCODING = 1
 	SETUPTOOLS_ENFORCE_DEPRECATION = {env:SETUPTOOLS_ENFORCE_DEPRECATION:1}
 commands =
+	pyright --threads
 	pytest {posargs}
 usedevelop = True
 extras =