diff --git a/ollama/_client.py b/ollama/_client.py
index 13dd6441..e768c604 100644
--- a/ollama/_client.py
+++ b/ollama/_client.py
@@ -5,6 +5,7 @@
 import platform
 import sys
 import urllib.parse
+from enum import Enum
 from hashlib import sha256
 from os import PathLike
 from pathlib import Path
@@ -217,7 +218,7 @@ def generate(
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
     raw: bool = False,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     images: Optional[Sequence[Union[str, bytes, Image]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
@@ -241,7 +242,7 @@ def generate(
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
     raw: bool = False,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     images: Optional[Sequence[Union[str, bytes, Image]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
@@ -264,7 +265,7 @@ def generate(
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
     raw: Optional[bool] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     images: Optional[Sequence[Union[str, bytes, Image]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
@@ -320,7 +321,7 @@ def chat(
     think: Optional[Union[bool, str]] = None,
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
   ) -> ChatResponse: ...
@@ -336,7 +337,7 @@ def chat(
     think: Optional[Union[bool, str]] = None,
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
   ) -> Iterator[ChatResponse]: ...
@@ -351,7 +352,7 @@ def chat(
     think: Optional[Union[bool, str]] = None,
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
   ) -> Union[ChatResponse, Iterator[ChatResponse]]:
@@ -873,7 +874,7 @@ async def generate(
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
     raw: bool = False,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     images: Optional[Sequence[Union[str, bytes, Image]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
@@ -897,7 +898,7 @@ async def generate(
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
     raw: bool = False,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     images: Optional[Sequence[Union[str, bytes, Image]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
@@ -920,7 +921,7 @@ async def generate(
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
     raw: Optional[bool] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     images: Optional[Sequence[Union[str, bytes, Image]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
@@ -975,7 +976,7 @@ async def chat(
     think: Optional[Union[bool, str]] = None,
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
   ) -> ChatResponse: ...
@@ -991,7 +992,7 @@ async def chat(
     think: Optional[Union[bool, str]] = None,
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
   ) -> AsyncIterator[ChatResponse]: ...
@@ -1006,7 +1007,7 @@ async def chat(
     think: Optional[Union[bool, str]] = None,
     logprobs: Optional[bool] = None,
     top_logprobs: Optional[int] = None,
-    format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None,
+    format: Optional[Union[Literal['', 'json'], JsonSchemaValue, Type[Enum]]] = None,
     options: Optional[Union[Mapping[str, Any], Options]] = None,
     keep_alive: Optional[Union[float, str]] = None,
   ) -> Union[ChatResponse, AsyncIterator[ChatResponse]]:
diff --git a/ollama/_types.py b/ollama/_types.py
index cf7264b5..942a0538 100644
--- a/ollama/_types.py
+++ b/ollama/_types.py
@@ -2,6 +2,7 @@
 import json
 from base64 import b64decode, b64encode
 from datetime import datetime
+from enum import Enum
 from pathlib import Path
 from typing import Any, Dict, List, Mapping, Optional, Sequence, Union
 
@@ -10,6 +11,8 @@
   ByteSize,
   ConfigDict,
   Field,
+  TypeAdapter,
+  field_validator,
   model_serializer,
 )
 from pydantic.json_schema import JsonSchemaValue
@@ -154,6 +157,13 @@ class BaseGenerateRequest(BaseStreamableRequest):
   format: Optional[Union[Literal['', 'json'], JsonSchemaValue]] = None
   'Format of the response.'
 
+  @field_validator('format', mode='before')
+  @classmethod
+  def _enum_format(cls, value: Any) -> Any:
+    if isinstance(value, type) and issubclass(value, Enum):
+      return TypeAdapter(value).json_schema()
+    return value
+
   keep_alive: Optional[Union[float, str]] = None
   'Keep model alive for the specified duration.'
 
diff --git a/tests/test_client.py b/tests/test_client.py
index c212a11d..81a0bee3 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -4,10 +4,13 @@
 import os
 import re
 import tempfile
+from enum import Enum
 from pathlib import Path
 from typing import Any
 
 import pytest
+from httpx import MockTransport
+from httpx import Request as httpxRequest
 from httpx import Response as httpxResponse
 from pydantic import BaseModel
 from pytest_httpserver import HTTPServer, URIPattern
@@ -22,6 +25,35 @@
 pytestmark = pytest.mark.anyio
 
 
+class Answer(Enum):
+  yes = 'yes'
+  no = 'no'
+
+
+@pytest.mark.parametrize('method', ['chat', 'generate'])
+def test_client_accepts_enum_response_format(method: str):
+  def respond(request: httpxRequest) -> httpxResponse:
+    assert request.url.path == f'/api/{method}'
+    assert json.loads(request.content)['format'] == {'enum': ['yes', 'no'], 'title': 'Answer', 'type': 'string'}
+    return httpxResponse(200, json={'model': 'dummy', 'message': {'role': 'assistant', 'content': '"yes"'}} if method == 'chat' else {'model': 'dummy', 'response': '"yes"'})
+
+  with Client(transport=MockTransport(respond)) as client:
+    response = getattr(client, method)(model='dummy', format=Answer)
+  assert response.model == 'dummy'
+
+
+@pytest.mark.parametrize('method', ['chat', 'generate'])
+async def test_async_client_accepts_enum_response_format(method: str):
+  def respond(request: httpxRequest) -> httpxResponse:
+    assert request.url.path == f'/api/{method}'
+    assert json.loads(request.content)['format'] == {'enum': ['yes', 'no'], 'title': 'Answer', 'type': 'string'}
+    return httpxResponse(200, json={'model': 'dummy', 'message': {'role': 'assistant', 'content': '"yes"'}} if method == 'chat' else {'model': 'dummy', 'response': '"yes"'})
+
+  async with AsyncClient(transport=MockTransport(respond)) as client:
+    response = await getattr(client, method)(model='dummy', format=Answer)
+  assert response.model == 'dummy'
+
+
 @pytest.fixture
 def anyio_backend():
   return 'asyncio'