diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a92044f15b..0bd7ee3d57 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -56,7 +56,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.8"
diff --git a/.github/workflows/contrib-openai.yml b/.github/workflows/contrib-openai.yml
index 9a99caec96..5d74c59022 100644
--- a/.github/workflows/contrib-openai.yml
+++ b/.github/workflows/contrib-openai.yml
@@ -273,7 +273,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.12"]
+        python-version: ["3.13"]
     runs-on: ${{ matrix.os }}
     environment: openai1
     steps:
diff --git a/.github/workflows/contrib-tests.yml b/.github/workflows/contrib-tests.yml
index 9411222f87..9e93490ea7 100644
--- a/.github/workflows/contrib-tests.yml
+++ b/.github/workflows/contrib-tests.yml
@@ -29,7 +29,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [macos-latest, windows-2019]
+        os: [macos-latest, windows-latest]
         python-version: ["3.9", "3.10", "3.11"]
         exclude:
           - os: macos-latest
@@ -168,7 +168,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: ["3.10"]
     steps:
       - uses: actions/checkout@v4
@@ -203,7 +203,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: ["3.11"]
     steps:
       - uses: actions/checkout@v4
@@ -238,8 +238,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.13"]
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
@@ -273,8 +273,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.13"]
     steps:
       - uses: actions/checkout@v4
         with:
@@ -300,7 +300,7 @@ jobs:
         run: |
           pytest test/agentchat/contrib/test_img_utils.py test/agentchat/contrib/test_lmm.py test/agentchat/contrib/test_llava.py test/agentchat/contrib/capabilities/test_vision_capability.py --skip-openai
       - name: Image Gen Coverage
-        if: ${{ matrix.os != 'windows-2019' && matrix.python-version != '3.12' }}
+        if: ${{ matrix.os != 'windows-latest' && matrix.python-version != '3.13' }}
         run: |
           pytest test/agentchat/contrib/capabilities/test_image_generation_capability.py --skip-openai
       - name: Upload coverage to Codecov
@@ -314,8 +314,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.9"
@@ -354,7 +354,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: ["3.11"]
     steps:
       - uses: actions/checkout@v4
@@ -389,7 +389,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: ["3.11"]
     steps:
       - uses: actions/checkout@v4
@@ -421,7 +421,7 @@ jobs:
       fail-fast: false
       matrix:
         os: ["ubuntu-latest", "windows-latest", "macos-latest"]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps:
       - uses: actions/checkout@v4
@@ -462,8 +462,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.9"
@@ -502,8 +502,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.9"
@@ -542,8 +542,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.9"
@@ -582,8 +582,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.9"
@@ -622,7 +622,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
     steps:
       - uses: actions/checkout@v4
         with:
@@ -658,8 +658,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.9"
@@ -698,8 +698,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-2019]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
         exclude:
           - os: macos-latest
             python-version: "3.9"
diff --git a/.github/workflows/openai.yml b/.github/workflows/openai.yml
index a9ab8e9e0c..7dcf3175ba 100644
--- a/.github/workflows/openai.yml
+++ b/.github/workflows/openai.yml
@@ -25,7 +25,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
     runs-on: ${{ matrix.os }}
     environment: openai1
     services:
diff --git a/.github/workflows/type-check.yml b/.github/workflows/type-check.yml
index c66fb6ad7b..617dbe634c 100644
--- a/.github/workflows/type-check.yml
+++ b/.github/workflows/type-check.yml
@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
diff --git a/README.md b/README.md
index 396e669d1e..e2aa0dff71 100644
--- a/README.md
+++ b/README.md
@@ -130,7 +130,7 @@ Find detailed instructions for users [here](https://ag2ai.github.io/ag2/docs/ins
 
 ### Option 2. Install AG2 Locally
 
-AG2 requires **Python version >= 3.8, < 3.13**. It can be installed from pip:
+AG2 requires **Python version >= 3.8, < 3.14**. It can be installed from pip:
 
 ```bash
 pip install ag2
diff --git a/autogen/agentchat/contrib/llamaindex_conversable_agent.py b/autogen/agentchat/contrib/llamaindex_conversable_agent.py
index b5bc79dec1..e883e76714 100644
--- a/autogen/agentchat/contrib/llamaindex_conversable_agent.py
+++ b/autogen/agentchat/contrib/llamaindex_conversable_agent.py
@@ -16,6 +16,15 @@
     from llama_index.core.agent.runner.base import AgentRunner
     from llama_index.core.base.llms.types import ChatMessage
     from llama_index.core.chat_engine.types import AgentChatResponse
+    from pydantic import BaseModel
+
+    # Add Pydantic configuration to allow arbitrary types
+    # Added to mitigate PydanticSchemaGenerationError
+    class Config:
+        arbitrary_types_allowed = True
+
+    BaseModel.model_config = Config
+
 except ImportError as e:
     logger.fatal("Failed to import llama-index. Try running 'pip install llama-index'")
     raise e
diff --git a/setup.py b/setup.py
index 735a89f07d..435fa1a76c 100644
--- a/setup.py
+++ b/setup.py
@@ -30,7 +30,8 @@
     "termcolor",
     "flaml",
     # numpy is installed by flaml, but we want to pin the version to below 2.x (see https://github.com/microsoft/autogen/issues/1960)
-    "numpy>=1.17.0,<2",
+    "numpy>=2.1; python_version>='3.13'",  # numpy 2.1+ required for Python 3.13
+    "numpy>=1.24.0,<2.0.0; python_version<'3.13'",  # numpy 1.24+ for older Python versions
     "python-dotenv",
     "tiktoken",
     # Disallowing 2.6.0 can be removed when this is fixed https://github.com/pydantic/pydantic/issues/8705
@@ -135,5 +136,5 @@
         "Operating System :: OS Independent",
     ],
     license="Apache Software License 2.0",
-    python_requires=">=3.8,<3.13",
+    python_requires=">=3.8,<3.14",
 )
diff --git a/test/agentchat/contrib/graph_rag/test_falkor_graph_rag.py b/test/agentchat/contrib/graph_rag/test_falkor_graph_rag.py
index 8814479da9..5b61454e9e 100644
--- a/test/agentchat/contrib/graph_rag/test_falkor_graph_rag.py
+++ b/test/agentchat/contrib/graph_rag/test_falkor_graph_rag.py
@@ -3,7 +3,7 @@
 import pytest
 from conftest import reason, skip_openai  # noqa: E402
 from graphrag_sdk import KnowledgeGraph, Source
-from graphrag_sdk.schema import Schema
+from graphrag_sdk.ontology import Ontology
 
 try:
     from autogen.agentchat.contrib.graph_rag.document import (
@@ -34,7 +34,7 @@ def test_falkor_db_query_engine():
     3. Query it with a question and verify the result contains the critical information.
     """
     # Arrange
-    test_schema = Schema()
+    test_schema = Ontology()
     actor = test_schema.add_entity("Actor").add_attribute("name", str, unique=True)
     movie = test_schema.add_entity("Movie").add_attribute("title", str, unique=True)
     test_schema.add_relation("ACTED", actor, movie)
diff --git a/test/agentchat/test_function_and_tool_calling.py b/test/agentchat/test_function_and_tool_calling.py
index cd7064cd7b..eaaea6a8a9 100644
--- a/test/agentchat/test_function_and_tool_calling.py
+++ b/test/agentchat/test_function_and_tool_calling.py
@@ -5,12 +5,16 @@
 # Portions derived from  https://github.com/microsoft/autogen are under the MIT License.
 # SPDX-License-Identifier: MIT
 import json
+import sys
 from typing import Any, Callable, Dict, List
 
 import pytest
 
 from autogen.agentchat.conversable_agent import ConversableAgent
 
+# Cater for Python version 3.13+ changes in json error messages
+PYTHON131PLUS = sys.version_info >= (3, 13)
+
 
 def _tool_func_1(arg1: str, arg2: str) -> str:
     return f"_tool_func_1: {arg1} {arg2}"
@@ -107,6 +111,20 @@ async def _a_tool_func_error(arg1: str, arg2: str) -> str:
     "content": "Error: Expecting property name enclosed in double quotes: line 1 column 37 (char 36)\n The argument must be in JSON format.\n\n_tool_func_2: value3 value4",
 }
 
+# Python 3.13+ has different json error messages
+_tool_use_message_1_bad_json_expected_reply_313 = {
+    "role": "tool",
+    "tool_responses": [
+        {
+            "tool_call_id": "1",
+            "role": "tool",
+            "content": "Error: Illegal trailing comma before end of object: line 1 column 36 (char 35)\n The argument must be in JSON format.",
+        },
+        {"tool_call_id": "2", "role": "tool", "content": "_tool_func_2: value3 value4"},
+    ],
+    "content": "Error: Illegal trailing comma before end of object: line 1 column 36 (char 35)\n The argument must be in JSON format.\n\n_tool_func_2: value3 value4",
+}
+
 _tool_use_message_1_error_expected_reply = {
     "role": "tool",
     "tool_responses": [
@@ -163,6 +181,13 @@ async def _a_tool_func_error(arg1: str, arg2: str) -> str:
     "content": "Error: Expecting property name enclosed in double quotes: line 1 column 37 (char 36)\n The argument must be in JSON format.",
 }
 
+# Python 3.13+ has different json error messages
+_function_use_message_1_bad_json_expected_reply_313 = {
+    "name": "_tool_func_1",
+    "role": "function",
+    "content": "Error: Illegal trailing comma before end of object: line 1 column 36 (char 35)\n The argument must be in JSON format.",
+}
+
 _function_use_message_1_error_expected_reply = {
     "name": "_tool_func_1",
     "role": "function",
@@ -240,7 +265,14 @@ def test_generate_function_call_reply_on_function_call_message(is_function_async
     # bad JSON
     messages = [_function_use_message_1_bad_json]
     finished, retval = agent.generate_function_call_reply(messages)
-    assert (finished, retval) == (True, _function_use_message_1_bad_json_expected_reply)
+    assert (finished, retval) == (
+        True,
+        (
+            _function_use_message_1_bad_json_expected_reply_313
+            if PYTHON131PLUS
+            else _function_use_message_1_bad_json_expected_reply
+        ),
+    )
 
     # tool call
     messages = [_tool_use_message_1]
@@ -282,7 +314,14 @@ async def test_a_generate_function_call_reply_on_function_call_message(is_functi
     # bad JSON
     messages = [_function_use_message_1_bad_json]
     finished, retval = await agent.a_generate_function_call_reply(messages)
-    assert (finished, retval) == (True, _function_use_message_1_bad_json_expected_reply)
+    assert (finished, retval) == (
+        True,
+        (
+            _function_use_message_1_bad_json_expected_reply_313
+            if PYTHON131PLUS
+            else _function_use_message_1_bad_json_expected_reply
+        ),
+    )
 
     # tool call
     messages = [_tool_use_message_1]
@@ -323,7 +362,14 @@ def test_generate_tool_calls_reply_on_function_call_message(is_function_async: b
     # bad JSON
     messages = [_tool_use_message_1_bad_json]
     finished, retval = agent.generate_tool_calls_reply(messages)
-    assert (finished, retval) == (True, _tool_use_message_1_bad_json_expected_reply)
+    assert (finished, retval) == (
+        True,
+        (
+            _tool_use_message_1_bad_json_expected_reply_313
+            if PYTHON131PLUS
+            else _tool_use_message_1_bad_json_expected_reply
+        ),
+    )
 
     # function call
     messages = [_function_use_message_1]
@@ -365,7 +411,14 @@ async def test_a_generate_tool_calls_reply_on_function_call_message(is_function_
     # bad JSON
     messages = [_tool_use_message_1_bad_json]
     finished, retval = await agent.a_generate_tool_calls_reply(messages)
-    assert (finished, retval) == (True, _tool_use_message_1_bad_json_expected_reply)
+    assert (finished, retval) == (
+        True,
+        (
+            _tool_use_message_1_bad_json_expected_reply_313
+            if PYTHON131PLUS
+            else _tool_use_message_1_bad_json_expected_reply
+        ),
+    )
 
     # function call
     messages = [_function_use_message_1]
diff --git a/test/test_notebook.py b/test/test_notebook.py
index d6db43d711..fb746a2ecb 100755
--- a/test/test_notebook.py
+++ b/test/test_notebook.py
@@ -54,8 +54,8 @@ def run_notebook(input_nb, output_nb="executed_openai_notebook.ipynb", save=Fals
 
 
 @pytest.mark.skipif(
-    skip or not sys.version.startswith("3.10"),
-    reason="do not run if openai is not installed or py!=3.10",
+    skip or not sys.version.startswith("3.13"),
+    reason="do not run if openai is not installed or py!=3.13",
 )
 def test_agentchat_auto_feedback_from_code(save=False):
     run_notebook("agentchat_auto_feedback_from_code_execution.ipynb", save=save)
@@ -86,8 +86,8 @@ def test_agentchat_function_call_currency_calculator(save=False):
 
 
 @pytest.mark.skipif(
-    skip or not sys.version.startswith("3.11"),
-    reason="do not run if openai is not installed or py!=3.11",
+    skip or not sys.version.startswith("3.13"),
+    reason="do not run if openai is not installed or py!=3.13",
 )
 def test_agentchat_function_call_async(save=False):
     run_notebook("agentchat_function_call_async.ipynb", save=save)
@@ -118,8 +118,8 @@ def test_agentchat_groupchat_finite_state_machine(save=False):
 
 
 @pytest.mark.skipif(
-    skip or not sys.version.startswith("3.10"),
-    reason="do not run if openai is not installed or py!=3.10",
+    skip or not sys.version.startswith("3.11"),
+    reason="do not run if openai is not installed or py!=3.11",
 )
 def test_agentchat_cost_token_tracking(save=False):
     run_notebook("agentchat_cost_token_tracking.ipynb", save=save)
diff --git a/website/docs/installation/Installation.mdx b/website/docs/installation/Installation.mdx
index 51f0e4cbbe..a74100fcd1 100644
--- a/website/docs/installation/Installation.mdx
+++ b/website/docs/installation/Installation.mdx
@@ -66,7 +66,7 @@ When installing AutoGen locally, we recommend using a virtual environment for th
 
 ## Install AutoGen
 
-AutoGen requires **Python version >= 3.8, < 3.13**. It can be installed from pip:
+AutoGen requires **Python version >= 3.8, < 3.14**. It can be installed from pip:
 
 ```bash
 pip install autogen