diff --git a/src/openai/_models.py b/src/openai/_models.py
index 810e49dfc5..4711ffd007 100644
--- a/src/openai/_models.py
+++ b/src/openai/_models.py
@@ -799,7 +799,7 @@ class GenericModel(BaseGenericModel, BaseModel):
 if not PYDANTIC_V1:
     from pydantic import TypeAdapter as _TypeAdapter
 
-    _CachedTypeAdapter = cast("TypeAdapter[object]", lru_cache(maxsize=None)(_TypeAdapter))
+    _CachedTypeAdapter = cast("TypeAdapter[object]", lru_cache(maxsize=4096)(_TypeAdapter))
 
     if TYPE_CHECKING:
         from pydantic import TypeAdapter