diff --git a/outlines/models/openai.py b/outlines/models/openai.py
index cedb37420..8625f4d3d 100644
--- a/outlines/models/openai.py
+++ b/outlines/models/openai.py
@@ -414,10 +414,16 @@ def call(*args, **kwargs):
     return call
 
 
-def openai(
+@functools.singledispatch
+def openai(model_or_client, *args, **kwargs):
+    return OpenAI(model_or_client, *args, **kwargs)
+
+
+@openai.register(str)
+def openai_model(
     model_name: str,
-    api_key: Optional[str] = None,
     config: Optional[OpenAIConfig] = None,
+    **openai_client_params,
 ):
     try:
         import tiktoken
@@ -432,7 +438,7 @@ def openai(
     else:
         config = OpenAIConfig(model=model_name)
 
-    client = AsyncOpenAI(api_key=api_key)
+    client = AsyncOpenAI(**openai_client_params)
     tokenizer = tiktoken.encoding_for_model(model_name)
 
     return OpenAI(client, config, tokenizer)
@@ -441,10 +447,8 @@ def openai(
 def azure_openai(
     deployment_name: str,
     model_name: Optional[str] = None,
-    azure_endpoint: Optional[str] = None,
-    api_version: Optional[str] = None,
-    api_key: Optional[str] = None,
     config: Optional[OpenAIConfig] = None,
+    **azure_openai_client_params,
 ):
     try:
         import tiktoken
@@ -459,9 +463,7 @@ def azure_openai(
     if config is None:
         config = OpenAIConfig(model=deployment_name)
 
-    client = AsyncAzureOpenAI(
-        azure_endpoint=azure_endpoint, api_version=api_version, api_key=api_key
-    )
+    client = AsyncAzureOpenAI(**azure_openai_client_params)
     tokenizer = tiktoken.encoding_for_model(model_name or deployment_name)
 
     return OpenAI(client, config, tokenizer)