diff --git a/discord/webhook/async_.py b/discord/webhook/async_.py
index d1ed1ade0..fac601f32 100644
--- a/discord/webhook/async_.py
+++ b/discord/webhook/async_.py
@@ -32,6 +32,7 @@ import re
 from urllib.parse import quote as urlquote
 from typing import Any, Dict, List, Literal, NamedTuple, Optional, TYPE_CHECKING, Tuple, Union, overload
 from contextvars import ContextVar
+import weakref
 
 import aiohttp
 
@@ -95,7 +96,7 @@ class AsyncDeferredLock:
 
 class AsyncWebhookAdapter:
     def __init__(self):
-        self._locks: Dict[Any, asyncio.Lock] = {}
+        self._locks: weakref.WeakValueDictionary[Any, asyncio.Lock] = weakref.WeakValueDictionary()
 
     async def request(
         self,
diff --git a/discord/webhook/sync.py b/discord/webhook/sync.py
index 5c85a0365..3f7cd6018 100644
--- a/discord/webhook/sync.py
+++ b/discord/webhook/sync.py
@@ -38,6 +38,7 @@ import re
 
 from urllib.parse import quote as urlquote
 from typing import Any, Dict, List, Literal, Optional, TYPE_CHECKING, Tuple, Type, TypeVar, Union, overload
+import weakref
 
 from .. import utils
 from ..errors import InvalidArgument, HTTPException, Forbidden, NotFound, DiscordServerError
@@ -91,7 +92,7 @@ class DeferredLock:
 
 class WebhookAdapter:
     def __init__(self):
-        self._locks: Dict[Any, threading.Lock] = {}
+        self._locks: weakref.WeakValueDictionary[Any, threading.Lock] = weakref.WeakValueDictionary()
 
     def request(
         self,