diff --git a/src/openai/_models.py b/src/openai/_models.py
index 88afa40810..4aa2623bbc 100644
--- a/src/openai/_models.py
+++ b/src/openai/_models.py
@@ -3,6 +3,7 @@
 import inspect
 from typing import TYPE_CHECKING, Any, Type, Union, Generic, TypeVar, Callable, cast
 from datetime import date, datetime
+from functools import lru_cache
 from typing_extensions import (
     Unpack,
     Literal,
@@ -533,7 +534,12 @@ class GenericModel(BaseGenericModel, BaseModel):
 
 
 if PYDANTIC_V2:
-    from pydantic import TypeAdapter
+
+    if TYPE_CHECKING:
+      from pydantic import TypeAdapter
+    else:
+      from pydantic import TypeAdapter as _TypeAdapter
+      TypeAdapter = lru_cache(_TypeAdapter)   
 
     def _validate_non_model_type(*, type_: type[_T], value: object) -> _T:
         return TypeAdapter(type_).validate_python(value)