diff --git a/autogen/agentchat/conversable_agent.py b/autogen/agentchat/conversable_agent.py
index a3726678a45..bf10f465358 100644
--- a/autogen/agentchat/conversable_agent.py
+++ b/autogen/agentchat/conversable_agent.py
@@ -2039,15 +2039,18 @@ async def a_generate_init_message(self, **context) -> Union[str, Dict]:
         self._process_carryover(context)
         return context["message"]
 
-    def register_function(self, function_map: Dict[str, Callable]):
+    def register_function(self, function_map: Dict[str, Union[Callable, None]]):
         """Register functions to the agent.
 
         Args:
-            function_map: a dictionary mapping function names to functions.
+            function_map: a dictionary mapping function names to functions. if function_map[name] is None, the function will be removed from the function_map.
         """
-        for name in function_map.keys():
+        for name, func in function_map.items():
             self._assert_valid_name(name)
-        self._function_map.update(function_map)
+            if func is None and name not in self._function_map.keys():
+                warnings.warn(f"The function {name} to remove doesn't exist", name)
+
+        self._function_map = {name: func for name, func in function_map.items() if func is not None}
 
     def update_function_signature(self, func_sig: Union[str, Dict], is_remove: None):
         """update a function_signature in the LLM configuration for function_call.
diff --git a/test/agentchat/test_conversable_agent.py b/test/agentchat/test_conversable_agent.py
index b71a6341c87..bc7546b2ef3 100644
--- a/test/agentchat/test_conversable_agent.py
+++ b/test/agentchat/test_conversable_agent.py
@@ -559,6 +559,16 @@ def exec_sh(script: str) -> None:
         assert agent.function_map["python"] == exec_python
         assert agent.function_map["sh"] == exec_sh
 
+        # remove the functions
+        agent.register_function(
+            function_map={
+                "python": None,
+            }
+        )
+
+        assert set(agent.function_map.keys()) == {"sh"}
+        assert agent.function_map["sh"] == exec_sh
+
 
 def test__wrap_function_sync():
     CurrencySymbol = Literal["USD", "EUR"]