diff --git a/python/packages/autogen-agentchat/tests/test_group_chat.py b/python/packages/autogen-agentchat/tests/test_group_chat.py
index 971dec1ce54b..37763e866950 100644
--- a/python/packages/autogen-agentchat/tests/test_group_chat.py
+++ b/python/packages/autogen-agentchat/tests/test_group_chat.py
@@ -455,7 +455,7 @@ async def test_round_robin_group_chat_with_tools(runtime: AgentRuntime | None) -
             "TERMINATE",
         ],
         model_info={
-            "family": "gpt-4o",
+            "family": "gpt-4.1-nano",
             "function_calling": True,
             "json_output": True,
             "vision": True,
@@ -1272,7 +1272,7 @@ async def test_swarm_handoff_using_tool_calls(runtime: AgentRuntime | None) -> N
             "TERMINATE",
         ],
         model_info={
-            "family": "gpt-4o",
+            "family": "gpt-4.1-nano",
             "function_calling": True,
             "json_output": True,
             "vision": True,
@@ -1372,7 +1372,7 @@ async def test_swarm_with_parallel_tool_calls(runtime: AgentRuntime | None) -> N
             "TERMINATE",
         ],
         model_info={
-            "family": "gpt-4o",
+            "family": "gpt-4.1-nano",
             "function_calling": True,
             "json_output": True,
             "vision": True,
@@ -1562,12 +1562,14 @@ async def test_declarative_groupchats_with_config(runtime: AgentRuntime | None)
     # Create basic agents and components for testing
     agent1 = AssistantAgent(
         "agent_1",
-        model_client=OpenAIChatCompletionClient(model="gpt-4o-2024-05-13", api_key=""),
+        model_client=OpenAIChatCompletionClient(model="gpt-4.1-nano-2025-04-14", api_key=""),
         handoffs=["agent_2"],
     )
-    agent2 = AssistantAgent("agent_2", model_client=OpenAIChatCompletionClient(model="gpt-4o-2024-05-13", api_key=""))
+    agent2 = AssistantAgent(
+        "agent_2", model_client=OpenAIChatCompletionClient(model="gpt-4.1-nano-2025-04-14", api_key="")
+    )
     termination = MaxMessageTermination(4)
-    model_client = OpenAIChatCompletionClient(model="gpt-4o-2024-05-13", api_key="")
+    model_client = OpenAIChatCompletionClient(model="gpt-4.1-nano-2025-04-14", api_key="")
 
     # Test round robin - verify config is preserved
     round_robin = RoundRobinGroupChat(participants=[agent1, agent2], termination_condition=termination, max_turns=5)
diff --git a/python/packages/autogen-agentchat/tests/test_group_chat_endpoint.py b/python/packages/autogen-agentchat/tests/test_group_chat_endpoint.py
index d9081b161e47..142df272950f 100644
--- a/python/packages/autogen-agentchat/tests/test_group_chat_endpoint.py
+++ b/python/packages/autogen-agentchat/tests/test_group_chat_endpoint.py
@@ -98,7 +98,7 @@ async def test_selector_group_chat_openai() -> None:
         pytest.skip("OPENAI_API_KEY not set in environment variables.")
 
     model_client = OpenAIChatCompletionClient(
-        model="gpt-4o-mini",
+        model="gpt-4.1-nano",
         api_key=api_key,
     )
     await _test_selector_group_chat(model_client)
diff --git a/python/packages/autogen-core/tests/test_model_context.py b/python/packages/autogen-core/tests/test_model_context.py
index fbb984090215..7a37c30a220b 100644
--- a/python/packages/autogen-core/tests/test_model_context.py
+++ b/python/packages/autogen-core/tests/test_model_context.py
@@ -119,7 +119,7 @@ async def test_unbounded_model_context() -> None:
 @pytest.mark.parametrize(
     "model_client,token_limit",
     [
-        (OpenAIChatCompletionClient(model="gpt-4o", temperature=0.0, api_key="test"), 30),
+        (OpenAIChatCompletionClient(model="gpt-4.1-nano", temperature=0.0, api_key="test"), 30),
         (OllamaChatCompletionClient(model="llama3.3"), 20),
     ],
     ids=["openai", "ollama"],
@@ -159,7 +159,7 @@ async def test_token_limited_model_context_with_token_limit(
 @pytest.mark.parametrize(
     "model_client",
     [
-        OpenAIChatCompletionClient(model="gpt-4o", temperature=0.0, api_key="test_key"),
+        OpenAIChatCompletionClient(model="gpt-4.1-nano", temperature=0.0, api_key="test_key"),
         OllamaChatCompletionClient(model="llama3.3"),
     ],
     ids=["openai", "ollama"],
@@ -182,7 +182,7 @@ async def test_token_limited_model_context_without_token_limit(model_client: Cha
 @pytest.mark.parametrize(
     "model_client,token_limit",
     [
-        (OpenAIChatCompletionClient(model="gpt-4o", temperature=0.0, api_key="test"), 60),
+        (OpenAIChatCompletionClient(model="gpt-4.1-nano", temperature=0.0, api_key="test"), 60),
         (OllamaChatCompletionClient(model="llama3.3"), 50),
     ],
     ids=["openai", "ollama"],
diff --git a/python/packages/autogen-ext/tests/models/test_openai_model_client.py b/python/packages/autogen-ext/tests/models/test_openai_model_client.py
index 263f57887162..3e4d6dccfa85 100644
--- a/python/packages/autogen-ext/tests/models/test_openai_model_client.py
+++ b/python/packages/autogen-ext/tests/models/test_openai_model_client.py
@@ -95,7 +95,7 @@ class MockChunkEvent(BaseModel):
 
 
 async def _mock_create_stream(*args: Any, **kwargs: Any) -> AsyncGenerator[ChatCompletionChunk, None]:
-    model = resolve_model(kwargs.get("model", "gpt-4o"))
+    model = resolve_model(kwargs.get("model", "gpt-4.1-nano"))
     mock_chunks_content = ["Hello", " Another Hello", " Yet Another Hello"]
 
     # The openai api implementations (OpenAI and Litellm) stream chunks of tokens
@@ -167,7 +167,7 @@ async def _mock_create_stream(*args: Any, **kwargs: Any) -> AsyncGenerator[ChatC
 
 async def _mock_create(*args: Any, **kwargs: Any) -> ChatCompletion | AsyncGenerator[ChatCompletionChunk, None]:
     stream = kwargs.get("stream", False)
-    model = resolve_model(kwargs.get("model", "gpt-4o"))
+    model = resolve_model(kwargs.get("model", "gpt-4.1-nano"))
     if not stream:
         await asyncio.sleep(0.1)
         return ChatCompletion(
@@ -186,7 +186,7 @@ async def _mock_create(*args: Any, **kwargs: Any) -> ChatCompletion | AsyncGener
 
 @pytest.mark.asyncio
 async def test_openai_chat_completion_client() -> None:
-    client = OpenAIChatCompletionClient(model="gpt-4o", api_key="api_key")
+    client = OpenAIChatCompletionClient(model="gpt-4.1-nano", api_key="api_key")
     assert client
 
 
@@ -198,7 +198,7 @@ async def test_openai_chat_completion_client_with_gemini_model() -> None:
 
 @pytest.mark.asyncio
 async def test_openai_chat_completion_client_serialization() -> None:
-    client = OpenAIChatCompletionClient(model="gpt-4o", api_key="sk-password")
+    client = OpenAIChatCompletionClient(model="gpt-4.1-nano", api_key="sk-password")
     assert client
     config = client.dump_component()
     assert config
@@ -467,7 +467,7 @@ async def run(self, args: MyArgs, cancellation_token: CancellationToken) -> MyRe
 
 @pytest.mark.asyncio
 async def test_json_mode(monkeypatch: pytest.MonkeyPatch) -> None:
-    model = "gpt-4o-2024-11-20"
+    model = "gpt-4.1-nano-2025-04-14"
 
     called_args = {}
 
@@ -562,7 +562,7 @@ class AgentResponse(BaseModel):
         thoughts: str
         response: Literal["happy", "sad", "neutral"]
 
-    model = "gpt-4o-2024-11-20"
+    model = "gpt-4.1-nano-2025-04-14"
 
     called_args = {}
 
@@ -654,7 +654,7 @@ class AgentResponse(BaseModel):
         thoughts: str
         response: Literal["happy", "sad", "neutral"]
 
-    model = "gpt-4o-2024-11-20"
+    model = "gpt-4.1-nano-2025-04-14"
 
     async def _mock_parse(*args: Any, **kwargs: Any) -> ParsedChatCompletion[AgentResponse]:
         return ParsedChatCompletion(
@@ -737,7 +737,7 @@ class AgentResponse(BaseModel):
         thoughts: str
         response: Literal["happy", "sad", "neutral"]
 
-    model = "gpt-4o-2024-11-20"
+    model = "gpt-4.1-nano-2025-04-14"
 
     async def _mock_parse(*args: Any, **kwargs: Any) -> ParsedChatCompletion[AgentResponse]:
         return ParsedChatCompletion(
@@ -813,7 +813,7 @@ class AgentResponse(BaseModel):
     chunked_content = [raw_content[i : i + 5] for i in range(0, len(raw_content), 5)]
     assert "".join(chunked_content) == raw_content
 
-    model = "gpt-4o-2024-11-20"
+    model = "gpt-4.1-nano-2025-04-14"
     mock_chunk_events = [
         MockChunkEvent(
             type="chunk",
@@ -886,7 +886,7 @@ class AgentResponse(BaseModel):
     chunked_content = [raw_content[i : i + 5] for i in range(0, len(raw_content), 5)]
     assert "".join(chunked_content) == raw_content
 
-    model = "gpt-4o-2024-11-20"
+    model = "gpt-4.1-nano-2025-04-14"
 
     # generate the list of mock chunk content
     mock_chunk_events = [
@@ -1265,7 +1265,7 @@ async def _mock_create(*args: Any, **kwargs: Any) -> ChatCompletion | AsyncGener
 
 @pytest.mark.asyncio
 async def test_tool_calling(monkeypatch: pytest.MonkeyPatch) -> None:
-    model = "gpt-4o-2024-05-13"
+    model = "gpt-4.1-nano-2025-04-14"
     chat_completions = [
         # Successful completion, single tool call
         ChatCompletion(
@@ -1622,7 +1622,7 @@ def openai_client(request: pytest.FixtureRequest) -> OpenAIChatCompletionClient:
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "model",
-    ["gpt-4o-mini", "gemini-1.5-flash", "claude-3-5-haiku-20241022"],
+    ["gpt-4.1-nano", "gemini-1.5-flash", "claude-3-5-haiku-20241022"],
 )
 async def test_model_client_basic_completion(model: str, openai_client: OpenAIChatCompletionClient) -> None:
     # Test basic completion
@@ -1639,7 +1639,7 @@ async def test_model_client_basic_completion(model: str, openai_client: OpenAICh
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "model",
-    ["gpt-4o-mini", "gemini-1.5-flash", "claude-3-5-haiku-20241022"],
+    ["gpt-4.1-nano", "gemini-1.5-flash", "claude-3-5-haiku-20241022"],
 )
 async def test_model_client_with_function_calling(model: str, openai_client: OpenAIChatCompletionClient) -> None:
     # Test tool calling
@@ -1716,7 +1716,7 @@ async def test_model_client_with_function_calling(model: str, openai_client: Ope
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "model",
-    ["gpt-4o-mini", "gemini-1.5-flash"],
+    ["gpt-4.1-nano", "gemini-1.5-flash"],
 )
 async def test_openai_structured_output_using_response_format(
     model: str, openai_client: OpenAIChatCompletionClient
@@ -1749,7 +1749,7 @@ class AgentResponse(BaseModel):
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "model",
-    ["gpt-4o-mini", "gemini-1.5-flash"],
+    ["gpt-4.1-nano", "gemini-1.5-flash"],
 )
 async def test_openai_structured_output(model: str, openai_client: OpenAIChatCompletionClient) -> None:
     class AgentResponse(BaseModel):
@@ -1769,7 +1769,7 @@ class AgentResponse(BaseModel):
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "model",
-    ["gpt-4o-mini", "gemini-1.5-flash"],
+    ["gpt-4.1-nano", "gemini-1.5-flash"],
 )
 async def test_openai_structured_output_with_streaming(model: str, openai_client: OpenAIChatCompletionClient) -> None:
     class AgentResponse(BaseModel):
@@ -1795,7 +1795,7 @@ class AgentResponse(BaseModel):
 @pytest.mark.parametrize(
     "model",
     [
-        "gpt-4o-mini",
+        "gpt-4.1-nano",
         # "gemini-1.5-flash", # Gemini models do not support structured output with tool calls from model client.
     ],
 )
@@ -1853,7 +1853,7 @@ def sentiment_analysis(text: str) -> str:
 @pytest.mark.parametrize(
     "model",
     [
-        "gpt-4o-mini",
+        "gpt-4.1-nano",
         # "gemini-1.5-flash", # Gemini models do not support structured output with tool calls from model client.
     ],
 )
@@ -2072,7 +2072,7 @@ async def test_add_name_prefixes(monkeypatch: pytest.MonkeyPatch) -> None:
 @pytest.mark.parametrize(
     "model",
     [
-        "gpt-4o-mini",
+        "gpt-4.1-nano",
         "gemini-1.5-flash",
         "claude-3-5-haiku-20241022",
     ],
@@ -2188,7 +2188,7 @@ async def test_system_message_not_merged_for_multiple_system_messages_true() ->
     mock_client = MagicMock()
     client = BaseOpenAIChatCompletionClient(
         client=mock_client,
-        create_args={"model": "gpt-4o"},
+        create_args={"model": "gpt-4.1-nano"},
         model_info={
             "vision": False,
             "function_calling": False,
@@ -2355,7 +2355,7 @@ async def test_empty_assistant_content_with_gemini(model: str, openai_client: Op
 @pytest.mark.parametrize(
     "model",
     [
-        "gpt-4o-mini",
+        "gpt-4.1-nano",
         "gemini-1.5-flash",
         "claude-3-5-haiku-20241022",
     ],
@@ -2402,7 +2402,7 @@ def get_regitered_transformer(client: OpenAIChatCompletionClient) -> Transformer
 @pytest.mark.parametrize(
     "model",
     [
-        "gpt-4o-mini",
+        "gpt-4.1-nano",
     ],
 )
 async def test_openai_model_unknown_message_type(model: str, openai_client: OpenAIChatCompletionClient) -> None:
diff --git a/python/packages/autogen-ext/tests/test_filesurfer_agent.py b/python/packages/autogen-ext/tests/test_filesurfer_agent.py
index 04fc46365475..ef7d58e71358 100644
--- a/python/packages/autogen-ext/tests/test_filesurfer_agent.py
+++ b/python/packages/autogen-ext/tests/test_filesurfer_agent.py
@@ -74,7 +74,7 @@ async def test_run_filesurfer(monkeypatch: pytest.MonkeyPatch) -> None:
 </html>""")
 
     # Mock the API calls
-    model = "gpt-4o-2024-05-13"
+    model = "gpt-4.1-nano-2025-04-14"
     chat_completions = [
         ChatCompletion(
             id="id1",
@@ -153,7 +153,7 @@ async def test_run_filesurfer(monkeypatch: pytest.MonkeyPatch) -> None:
 @pytest.mark.asyncio
 async def test_file_surfer_serialization() -> None:
     """Test that FileSurfer can be serialized and deserialized properly."""
-    model = "gpt-4o-2024-05-13"
+    model = "gpt-4.1-nano-2025-04-14"
     agent = FileSurfer(
         "FileSurfer",
         model_client=OpenAIChatCompletionClient(model=model, api_key=""),
diff --git a/python/packages/autogen-ext/tests/test_openai_assistant_agent.py b/python/packages/autogen-ext/tests/test_openai_assistant_agent.py
index d170e6b7f620..b76279c92a9f 100644
--- a/python/packages/autogen-ext/tests/test_openai_assistant_agent.py
+++ b/python/packages/autogen-ext/tests/test_openai_assistant_agent.py
@@ -202,7 +202,7 @@ def agent(client: AsyncOpenAI) -> OpenAIAssistantAgent:
     return OpenAIAssistantAgent(
         name="assistant",
         instructions="Help the user with their task.",
-        model="gpt-4o-mini",
+        model="gpt-4.1-nano",
         description="OpenAI Assistant Agent",
         client=client,
         tools=tools,
@@ -346,7 +346,7 @@ async def test_on_reset_behavior(client: AsyncOpenAI, cancellation_token: Cancel
     agent = OpenAIAssistantAgent(
         name="assistant",
         instructions="Help the user with their task.",
-        model="gpt-4o-mini",
+        model="gpt-4.1-nano",
         description="OpenAI Assistant Agent",
         client=client,
         thread_id=thread.id,
diff --git a/python/packages/autogen-ext/tests/test_websurfer_agent.py b/python/packages/autogen-ext/tests/test_websurfer_agent.py
index 37423bfe6a50..e9fb222d7316 100644
--- a/python/packages/autogen-ext/tests/test_websurfer_agent.py
+++ b/python/packages/autogen-ext/tests/test_websurfer_agent.py
@@ -61,7 +61,7 @@ async def mock_create(
 
 @pytest.mark.asyncio
 async def test_run_websurfer(monkeypatch: pytest.MonkeyPatch) -> None:
-    model = "gpt-4o-2024-05-13"
+    model = "gpt-4.1-nano-2025-04-14"
     chat_completions = [
         ChatCompletion(
             id="id2",
@@ -149,7 +149,7 @@ async def test_run_websurfer(monkeypatch: pytest.MonkeyPatch) -> None:
 
 @pytest.mark.asyncio
 async def test_run_websurfer_declarative(monkeypatch: pytest.MonkeyPatch) -> None:
-    model = "gpt-4o-2024-05-13"
+    model = "gpt-4.1-nano-2025-04-14"
     chat_completions = [
         ChatCompletion(
             id="id1",
diff --git a/python/packages/autogen-studio/tests/test_db_manager.py b/python/packages/autogen-studio/tests/test_db_manager.py
index 30227a064440..c2912a7d57ac 100644
--- a/python/packages/autogen-studio/tests/test_db_manager.py
+++ b/python/packages/autogen-studio/tests/test_db_manager.py
@@ -37,7 +37,7 @@ def sample_team(test_user: str) -> Team:
     agent = AssistantAgent(
         name="weather_agent",
         model_client=OpenAIChatCompletionClient(
-            model="gpt-4",
+            model="gpt-4.1-nano",
         ), 
     )
 
@@ -187,4 +187,4 @@ def test_initialize_database_scenarios(self, tmp_path, monkeypatch):
 
         finally:
             asyncio.run(db.close())
-            db.reset_db() 
\ No newline at end of file
+            db.reset_db() 
diff --git a/python/packages/autogen-studio/tests/test_team_manager.py b/python/packages/autogen-studio/tests/test_team_manager.py
index 0f25317d12ef..cf58ac78cbb6 100644
--- a/python/packages/autogen-studio/tests/test_team_manager.py
+++ b/python/packages/autogen-studio/tests/test_team_manager.py
@@ -21,7 +21,7 @@ def sample_config():
     agent = AssistantAgent(
         name="weather_agent",
         model_client=OpenAIChatCompletionClient(
-            model="gpt-4o-mini",
+            model="gpt-4.1-nano",
         ),
     )
     
@@ -146,4 +146,4 @@ async def mock_run_stream(*args, **kwargs):
             
             # Verify the last message is a TeamResult
             assert isinstance(streamed_messages[-1], type(mock_messages[-1]))
- 
\ No newline at end of file
+