diff --git a/.github/ISSUE_TEMPLATE/bug_report.yml b/.github/ISSUE_TEMPLATE/bug_report.yml
index 8ae7af0fff5..eb92f768a29 100644
--- a/.github/ISSUE_TEMPLATE/bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/bug_report.yml
@@ -86,6 +86,15 @@ body:
       $ python -m pip show multidict
   validations:
     required: true
+- type: textarea
+  attributes:
+    label: propcache Version
+    description: Attach your version of propcache.
+    render: console
+    value: |
+      $ python -m pip show propcache
+  validations:
+    required: true
 - type: textarea
   attributes:
     label: yarl Version
diff --git a/.gitignore b/.gitignore
index 7d38dd91998..62770ddc80a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,8 +37,6 @@
 aiohttp/_find_header.c
 aiohttp/_headers.html
 aiohttp/_headers.pxi
-aiohttp/_helpers.c
-aiohttp/_helpers.html
 aiohttp/_http_parser.c
 aiohttp/_http_parser.html
 aiohttp/_http_writer.c
diff --git a/CHANGES/9394.packaging.rst b/CHANGES/9394.packaging.rst
new file mode 100644
index 00000000000..456ac0f52c8
--- /dev/null
+++ b/CHANGES/9394.packaging.rst
@@ -0,0 +1,6 @@
+Switched to using the :mod:`propcache <propcache.api>` package for property caching
+-- by :user:`bdraco`.
+
+The :mod:`propcache <propcache.api>` package is derived from the property caching
+code in :mod:`yarl` and has been broken out to avoid maintaining it for multiple
+projects.
diff --git a/aiohttp/_helpers.pyi b/aiohttp/_helpers.pyi
deleted file mode 100644
index 1e358937024..00000000000
--- a/aiohttp/_helpers.pyi
+++ /dev/null
@@ -1,6 +0,0 @@
-from typing import Any
-
-class reify:
-    def __init__(self, wrapped: Any) -> None: ...
-    def __get__(self, inst: Any, owner: Any) -> Any: ...
-    def __set__(self, inst: Any, value: Any) -> None: ...
diff --git a/aiohttp/_helpers.pyx b/aiohttp/_helpers.pyx
deleted file mode 100644
index 5f089225dc8..00000000000
--- a/aiohttp/_helpers.pyx
+++ /dev/null
@@ -1,35 +0,0 @@
-
-cdef _sentinel = object()
-
-cdef class reify:
-    """Use as a class method decorator.  It operates almost exactly like
-    the Python `@property` decorator, but it puts the result of the
-    method it decorates into the instance dict after the first call,
-    effectively replacing the function it decorates with an instance
-    variable.  It is, in Python parlance, a data descriptor.
-
-    """
-
-    cdef object wrapped
-    cdef object name
-
-    def __init__(self, wrapped):
-        self.wrapped = wrapped
-        self.name = wrapped.__name__
-
-    @property
-    def __doc__(self):
-        return self.wrapped.__doc__
-
-    def __get__(self, inst, owner):
-        if inst is None:
-            return self
-        cdef dict cache = inst._cache
-        val = cache.get(self.name, _sentinel)
-        if val is _sentinel:
-            val = self.wrapped(inst)
-            cache[self.name] = val
-        return val
-
-    def __set__(self, inst, value):
-        raise AttributeError("reified property is read-only")
diff --git a/aiohttp/helpers.py b/aiohttp/helpers.py
index ec67abf5ebf..55b363003fc 100644
--- a/aiohttp/helpers.py
+++ b/aiohttp/helpers.py
@@ -49,6 +49,7 @@
 from urllib.request import getproxies, proxy_bypass
 
 from multidict import CIMultiDict, MultiDict, MultiDictProxy, MultiMapping
+from propcache.api import under_cached_property as reify
 from yarl import URL
 
 from . import hdrs
@@ -60,7 +61,7 @@
 else:
     import async_timeout
 
-__all__ = ("BasicAuth", "ChainMapProxy", "ETag")
+__all__ = ("BasicAuth", "ChainMapProxy", "ETag", "reify")
 
 PY_310 = sys.version_info >= (3, 10)
 
@@ -440,53 +441,6 @@ def is_expected_content_type(
     return expected_content_type in response_content_type
 
 
-class _TSelf(Protocol, Generic[_T]):
-    _cache: Dict[str, _T]
-
-
-class reify(Generic[_T]):
-    """Use as a class method decorator.
-
-    It operates almost exactly like
-    the Python `@property` decorator, but it puts the result of the
-    method it decorates into the instance dict after the first call,
-    effectively replacing the function it decorates with an instance
-    variable.  It is, in Python parlance, a data descriptor.
-    """
-
-    def __init__(self, wrapped: Callable[..., _T]) -> None:
-        self.wrapped = wrapped
-        self.__doc__ = wrapped.__doc__
-        self.name = wrapped.__name__
-
-    def __get__(self, inst: _TSelf[_T], owner: Optional[Type[Any]] = None) -> _T:
-        try:
-            try:
-                return inst._cache[self.name]
-            except KeyError:
-                val = self.wrapped(inst)
-                inst._cache[self.name] = val
-                return val
-        except AttributeError:
-            if inst is None:
-                return self
-            raise
-
-    def __set__(self, inst: _TSelf[_T], value: _T) -> None:
-        raise AttributeError("reified property is read-only")
-
-
-reify_py = reify
-
-try:
-    from ._helpers import reify as reify_c
-
-    if not NO_EXTENSIONS:
-        reify = reify_c  # type: ignore[misc,assignment]
-except ImportError:
-    pass
-
-
 def is_ip_address(host: Optional[str]) -> bool:
     """Check if host looks like an IP Address.
 
diff --git a/docs/conf.py b/docs/conf.py
index c8b41edda44..2deabea1b4f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -74,6 +74,7 @@
     "pytest": ("http://docs.pytest.org/en/latest/", None),
     "python": ("http://docs.python.org/3", None),
     "multidict": ("https://multidict.readthedocs.io/en/stable/", None),
+    "propcache": ("https://propcache.aio-libs.org/en/stable", None),
     "yarl": ("https://yarl.readthedocs.io/en/stable/", None),
     "aiosignal": ("https://aiosignal.readthedocs.io/en/stable/", None),
     "aiohttpjinja2": ("https://aiohttp-jinja2.readthedocs.io/en/stable/", None),
diff --git a/requirements/base.txt b/requirements/base.txt
index ead3ffeaea2..5d793411e2e 100644
--- a/requirements/base.txt
+++ b/requirements/base.txt
@@ -30,6 +30,8 @@ multidict==6.1.0
     #   yarl
 packaging==24.1
     # via gunicorn
+propcache==0.2.0
+    # via -r requirements/runtime-deps.in
 pycares==4.4.0
     # via aiodns
 pycparser==2.22
diff --git a/requirements/constraints.txt b/requirements/constraints.txt
index c3456fcea05..104c55dfa89 100644
--- a/requirements/constraints.txt
+++ b/requirements/constraints.txt
@@ -134,6 +134,8 @@ pluggy==1.5.0
     # via pytest
 pre-commit==3.5.0
     # via -r requirements/lint.in
+propcache==0.2.0
+    # via -r requirements/runtime-deps.in
 proxy-py==2.4.8
     # via
     #   -r requirements/lint.in
diff --git a/requirements/dev.txt b/requirements/dev.txt
index e62f22aad1a..65b8d49a5f4 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -131,6 +131,8 @@ pluggy==1.5.0
     # via pytest
 pre-commit==3.5.0
     # via -r requirements/lint.in
+propcache==0.2.0
+    # via -r requirements/runtime-deps.in
 proxy-py==2.4.8
     # via
     #   -r requirements/lint.in
diff --git a/requirements/runtime-deps.in b/requirements/runtime-deps.in
index 269118d5cb8..800420b9130 100644
--- a/requirements/runtime-deps.in
+++ b/requirements/runtime-deps.in
@@ -8,4 +8,5 @@ Brotli; platform_python_implementation == 'CPython'
 brotlicffi; platform_python_implementation != 'CPython'
 frozenlist >= 1.1.1
 multidict >=4.5, < 7.0
+propcache >= 0.2.0
 yarl >= 1.13.0, < 2.0
diff --git a/requirements/runtime-deps.txt b/requirements/runtime-deps.txt
index 777c7f19354..92c8b131bd0 100644
--- a/requirements/runtime-deps.txt
+++ b/requirements/runtime-deps.txt
@@ -26,6 +26,8 @@ multidict==6.1.0
     # via
     #   -r requirements/runtime-deps.in
     #   yarl
+propcache==0.2.0
+    # via -r requirements/runtime-deps.in
 pycares==4.4.0
     # via aiodns
 pycparser==2.22
diff --git a/setup.cfg b/setup.cfg
index af021dc2877..42ae12855b8 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -54,6 +54,7 @@ install_requires =
   async-timeout >= 4.0, < 5.0 ; python_version < "3.11"
   frozenlist >= 1.1.1
   multidict >=4.5, < 7.0
+  propcache >= 0.2.0
   yarl >= 1.13.0, < 2.0
 
 [options.exclude_package_data]
diff --git a/setup.py b/setup.py
index ce38273c573..cc66fe214ca 100644
--- a/setup.py
+++ b/setup.py
@@ -40,7 +40,6 @@
         define_macros=[("LLHTTP_STRICT_MODE", 0)],
         include_dirs=["vendor/llhttp/build"],
     ),
-    Extension("aiohttp._helpers", ["aiohttp/_helpers.c"]),
     Extension("aiohttp._http_writer", ["aiohttp/_http_writer.c"]),
 ]
 
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index 9da3565acd9..27de7174b27 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -2,12 +2,11 @@
 import base64
 import datetime
 import gc
-import platform
 import sys
 import weakref
 from math import ceil, modf
 from pathlib import Path
-from typing import Any, Dict, Iterator, Optional, Type, Union
+from typing import Dict, Iterator, Optional, Union
 from unittest import mock
 from urllib.request import getproxies_environment  # type: ignore[attr-defined]
 
@@ -24,9 +23,6 @@
     should_remove_content_length,
 )
 
-IS_PYPY = platform.python_implementation() == "PyPy"
-
-
 # ------------------- parse_mimetype ----------------------------------
 
 
@@ -227,59 +223,6 @@ def test_basic_auth_from_not_url() -> None:
         helpers.BasicAuth.from_url("http://user:pass@example.com")  # type: ignore[arg-type]
 
 
-class ReifyMixin:
-    reify: Type["helpers.reify[Any]"]
-
-    def test_reify(self) -> None:
-        class A:
-            def __init__(self) -> None:
-                self._cache: Dict[str, str] = {}
-
-            @self.reify  # type: ignore[misc]
-            def prop(self) -> int:
-                return 1
-
-        a = A()
-        assert 1 == a.prop
-
-    def test_reify_class(self) -> None:
-        class A:
-            def __init__(self) -> None:
-                self._cache: Dict[str, str] = {}
-
-            @self.reify  # type: ignore[misc]
-            def prop(self) -> int:
-                """Docstring."""
-                return 1
-
-        assert isinstance(A.prop, self.reify)  # type: ignore[arg-type]
-        assert "Docstring." == A.prop.__doc__  # type: ignore[arg-type]
-
-    def test_reify_assignment(self) -> None:
-        class A:
-            def __init__(self) -> None:
-                self._cache: Dict[str, str] = {}
-
-            @self.reify  # type: ignore[misc]
-            def prop(self) -> int:
-                return 1
-
-        a = A()
-
-        with pytest.raises(AttributeError):
-            a.prop = 123
-
-
-class TestPyReify(ReifyMixin):
-    reify = helpers.reify_py
-
-
-if not helpers.NO_EXTENSIONS and not IS_PYPY and hasattr(helpers, "reify_c"):
-
-    class TestCReify(ReifyMixin):
-        reify = helpers.reify_c  # type: ignore[attr-defined,assignment]
-
-
 # ----------------------------------- is_ip_address() ----------------------