diff --git a/litellm/llms/vertex_ai.py b/litellm/llms/vertex_ai.py
index 69feef63c..fc2d882af 100644
--- a/litellm/llms/vertex_ai.py
+++ b/litellm/llms/vertex_ai.py
@@ -87,6 +87,60 @@ class VertexAIConfig:
             and v is not None
         }
 
+    def get_supported_openai_params(self):
+        return [
+            "temperature",
+            "top_p",
+            "max_tokens",
+            "stream",
+            "tools",
+            "tool_choice",
+            "response_format",
+            "n",
+            "stop",
+        ]
+
+    def map_openai_params(self, non_default_params: dict, optional_params: dict):
+        for param, value in non_default_params.items():
+            if param == "temperature":
+                optional_params["temperature"] = value
+            if param == "top_p":
+                optional_params["top_p"] = value
+            if param == "stream":
+                optional_params["stream"] = value
+            if param == "n":
+                optional_params["candidate_count"] = value
+            if param == "stop":
+                if isinstance(value, str):
+                    optional_params["stop_sequences"] = [value]
+                elif isinstance(value, list):
+                    optional_params["stop_sequences"] = value
+            if param == "max_tokens":
+                optional_params["max_output_tokens"] = value
+            if param == "response_format" and value["type"] == "json_object":
+                optional_params["response_mime_type"] = "application/json"
+            if param == "tools" and isinstance(value, list):
+                from vertexai.preview import generative_models
+
+                gtool_func_declarations = []
+                for tool in value:
+                    gtool_func_declaration = generative_models.FunctionDeclaration(
+                        name=tool["function"]["name"],
+                        description=tool["function"].get("description", ""),
+                        parameters=tool["function"].get("parameters", {}),
+                    )
+                    gtool_func_declarations.append(gtool_func_declaration)
+                optional_params["tools"] = [
+                    generative_models.Tool(
+                        function_declarations=gtool_func_declarations
+                    )
+                ]
+            if param == "tool_choice" and (
+                isinstance(value, str) or isinstance(value, dict)
+            ):
+                pass
+        return optional_params
+
 
 import asyncio
 
@@ -822,8 +876,8 @@ async def async_completion(
                 tools=tools,
             )
 
-            if tools is not None and hasattr(
-                response.candidates[0].content.parts[0], "function_call"
+            if tools is not None and bool(
+                getattr(response.candidates[0].content.parts[0], "function_call", None)
             ):
                 function_call = response.candidates[0].content.parts[0].function_call
                 args_dict = {}
diff --git a/litellm/model_prices_and_context_window_backup.json b/litellm/model_prices_and_context_window_backup.json
index b650b799a..eedcaa493 100644
--- a/litellm/model_prices_and_context_window_backup.json
+++ b/litellm/model_prices_and_context_window_backup.json
@@ -1022,6 +1022,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-1.5-pro-preview-0215": { 
@@ -1033,6 +1034,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-1.5-pro-preview-0409": {
@@ -1044,6 +1046,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-experimental": {
@@ -1055,6 +1058,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": false,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-pro-vision": {
@@ -1281,6 +1285,7 @@
         "mode": "chat",
         "supports_function_calling": true,
         "supports_vision": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini/gemini-1.5-pro-latest": {
@@ -1293,6 +1298,7 @@
         "mode": "chat",
         "supports_function_calling": true,
         "supports_vision": true,
+        "supports_tool_choice": true, 
         "source": "https://ai.google.dev/models/gemini"
     },
     "gemini/gemini-pro-vision": {
diff --git a/litellm/utils.py b/litellm/utils.py
index 277d4f7b9..16a62be3b 100644
--- a/litellm/utils.py
+++ b/litellm/utils.py
@@ -4896,37 +4896,11 @@ def get_optional_params(
         )
         _check_valid_arg(supported_params=supported_params)
 
-        if temperature is not None:
-            optional_params["temperature"] = temperature
-        if top_p is not None:
-            optional_params["top_p"] = top_p
-        if stream:
-            optional_params["stream"] = stream
-        if n is not None:
-            optional_params["candidate_count"] = n
-        if stop is not None:
-            if isinstance(stop, str):
-                optional_params["stop_sequences"] = [stop]
-            elif isinstance(stop, list):
-                optional_params["stop_sequences"] = stop
-        if max_tokens is not None:
-            optional_params["max_output_tokens"] = max_tokens
-        if response_format is not None and response_format["type"] == "json_object":
-            optional_params["response_mime_type"] = "application/json"
-        if tools is not None and isinstance(tools, list):
-            from vertexai.preview import generative_models
+        optional_params = litellm.VertexAIConfig().map_openai_params(
+            non_default_params=non_default_params,
+            optional_params=optional_params,
+        )
 
-            gtool_func_declarations = []
-            for tool in tools:
-                gtool_func_declaration = generative_models.FunctionDeclaration(
-                    name=tool["function"]["name"],
-                    description=tool["function"].get("description", ""),
-                    parameters=tool["function"].get("parameters", {}),
-                )
-                gtool_func_declarations.append(gtool_func_declaration)
-            optional_params["tools"] = [
-                generative_models.Tool(function_declarations=gtool_func_declarations)
-            ]
         print_verbose(
             f"(end) INSIDE THE VERTEX AI OPTIONAL PARAM BLOCK - optional_params: {optional_params}"
         )
@@ -5628,17 +5602,7 @@ def get_supported_openai_params(model: str, custom_llm_provider: str):
     elif custom_llm_provider == "palm" or custom_llm_provider == "gemini":
         return ["temperature", "top_p", "stream", "n", "stop", "max_tokens"]
     elif custom_llm_provider == "vertex_ai":
-        return [
-            "temperature",
-            "top_p",
-            "max_tokens",
-            "stream",
-            "tools",
-            "tool_choice",
-            "response_format",
-            "n",
-            "stop",
-        ]
+        return litellm.VertexAIConfig().get_supported_openai_params()
     elif custom_llm_provider == "sagemaker":
         return ["stream", "temperature", "max_tokens", "top_p", "stop", "n"]
     elif custom_llm_provider == "aleph_alpha":
diff --git a/model_prices_and_context_window.json b/model_prices_and_context_window.json
index b650b799a..eedcaa493 100644
--- a/model_prices_and_context_window.json
+++ b/model_prices_and_context_window.json
@@ -1022,6 +1022,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-1.5-pro-preview-0215": { 
@@ -1033,6 +1034,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-1.5-pro-preview-0409": {
@@ -1044,6 +1046,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-experimental": {
@@ -1055,6 +1058,7 @@
         "litellm_provider": "vertex_ai-language-models",
         "mode": "chat",
         "supports_function_calling": false,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini-pro-vision": {
@@ -1281,6 +1285,7 @@
         "mode": "chat",
         "supports_function_calling": true,
         "supports_vision": true,
+        "supports_tool_choice": true, 
         "source": "https://cloud.google.com/vertex-ai/generative-ai/docs/learn/models#foundation_models"
     },
     "gemini/gemini-1.5-pro-latest": {
@@ -1293,6 +1298,7 @@
         "mode": "chat",
         "supports_function_calling": true,
         "supports_vision": true,
+        "supports_tool_choice": true, 
         "source": "https://ai.google.dev/models/gemini"
     },
     "gemini/gemini-pro-vision": {