diff --git a/CHANGES/7677.bugfix b/CHANGES/7677.bugfix
new file mode 100644
index 00000000000..ca20004121a
--- /dev/null
+++ b/CHANGES/7677.bugfix
@@ -0,0 +1 @@
+Changed ``AppKey`` warning to ``web.NotAppKeyWarning`` and stop it being displayed by default. -- by :user:`Dreamsorcerer`
diff --git a/aiohttp/web.py b/aiohttp/web.py
index f87d57988be..242f7a96ced 100644
--- a/aiohttp/web.py
+++ b/aiohttp/web.py
@@ -3,6 +3,7 @@
 import os
 import socket
 import sys
+import warnings
 from argparse import ArgumentParser
 from collections.abc import Iterable
 from importlib import import_module
@@ -83,6 +84,7 @@
     HTTPUseProxy,
     HTTPVariantAlsoNegotiates,
     HTTPVersionNotSupported,
+    NotAppKeyWarning,
 )
 from .web_fileresponse import FileResponse
 from .web_log import AccessLogger
@@ -139,6 +141,7 @@
     "Application",
     "CleanupError",
     # web_exceptions
+    "NotAppKeyWarning",
     "HTTPAccepted",
     "HTTPBadGateway",
     "HTTPBadRequest",
@@ -268,6 +271,9 @@
 except ImportError:  # pragma: no cover
     SSLContext = Any  # type: ignore[misc,assignment]
 
+# Only display warning when using -Wdefault, -We, -X dev or similar.
+warnings.filterwarnings("ignore", category=NotAppKeyWarning, append=True)
+
 HostSequence = TypingIterable[str]
 
 
diff --git a/aiohttp/web_app.py b/aiohttp/web_app.py
index 5be96084693..614c81fb9c4 100644
--- a/aiohttp/web_app.py
+++ b/aiohttp/web_app.py
@@ -31,6 +31,7 @@
 from .helpers import AppKey
 from .log import web_logger
 from .typedefs import Middleware
+from .web_exceptions import NotAppKeyWarning
 from .web_middlewares import _fix_request_current_app
 from .web_request import Request
 from .web_response import StreamResponse
@@ -173,6 +174,7 @@ def __setitem__(self, key: Union[str, AppKey[_T]], value: Any) -> None:
                 "It is recommended to use web.AppKey instances for keys.\n"
                 + "https://docs.aiohttp.org/en/stable/web_advanced.html"
                 + "#application-s-config",
+                category=NotAppKeyWarning,
                 stacklevel=2,
             )
         self._state[key] = value
diff --git a/aiohttp/web_exceptions.py b/aiohttp/web_exceptions.py
index 9ae61b43c9f..a4ba2e99bf2 100644
--- a/aiohttp/web_exceptions.py
+++ b/aiohttp/web_exceptions.py
@@ -71,6 +71,10 @@
 )
 
 
+class NotAppKeyWarning(UserWarning):
+    """Warning when not using AppKey in Application."""
+
+
 ############################################################
 # HTTP Exceptions
 ############################################################