diff --git a/lua/avante/llm.lua b/lua/avante/llm.lua
index f171b24..730385b 100644
--- a/lua/avante/llm.lua
+++ b/lua/avante/llm.lua
@@ -114,6 +114,10 @@ M.stream = function(opts)
     if data_match then Provider.parse_response(data_match, current_event_state, handler_opts) end
   end
 
+  local function parse_response_without_stream(data)
+    Provider.parse_response_without_stream(data, current_event_state, handler_opts)
+  end
+
   local completed = false
 
   local active_job
@@ -170,6 +174,14 @@ M.stream = function(opts)
           end
         end)
       end
+
+      -- If stream is not enabled, then handle the response here
+      if spec.body.stream == false and result.status == 200 then
+        vim.schedule(function()
+          completed = true
+          parse_response_without_stream(result.body)
+        end)
+      end
     end,
   })
 
diff --git a/lua/avante/providers/openai.lua b/lua/avante/providers/openai.lua
index 52e62b1..06a5f7b 100644
--- a/lua/avante/providers/openai.lua
+++ b/lua/avante/providers/openai.lua
@@ -9,7 +9,7 @@ local P = require("avante.providers")
 ---@field created integer
 ---@field model string
 ---@field system_fingerprint string
----@field choices? OpenAIResponseChoice[]
+---@field choices? OpenAIResponseChoice[] | OpenAIResponseChoiceComplete[]
 ---@field usage {prompt_tokens: integer, completion_tokens: integer, total_tokens: integer}
 ---
 ---@class OpenAIResponseChoice
@@ -18,6 +18,12 @@ local P = require("avante.providers")
 ---@field logprobs? integer
 ---@field finish_reason? "stop" | "length"
 ---
+---@class OpenAIResponseChoiceComplete
+---@field message OpenAIMessage
+---@field finish_reason "stop" | "length"
+---@field index integer
+---@field logprobs integer
+---
 ---@class OpenAIMessage
 ---@field role? "user" | "system" | "assistant"
 ---@field content string
@@ -50,10 +56,22 @@ M.parse_message = function(opts)
     end)
   end
 
-  return {
-    { role = "system", content = opts.system_prompt },
-    { role = "user", content = user_content },
-  }
+  local messages = {}
+  local provider = P[Config.provider]
+  local base, _ = P.parse_config(provider)
+
+  -- NOTE: Handle the case where the selected model is the `o1` model
+  -- "o1" models are "smart" enough to understand user prompt as a system prompt in this context
+  if base.model and string.find(base.model, "o1") then
+    table.insert(messages, { role = "user", content = opts.system_prompt })
+  else
+    table.insert(messages, { role = "system", content = opts.system_prompt })
+  end
+
+  -- User message after the prompt
+  table.insert(messages, { role = "user", content = user_content })
+
+  return messages
 end
 
 M.parse_response = function(data_stream, _, opts)
@@ -75,6 +93,18 @@ M.parse_response = function(data_stream, _, opts)
   end
 end
 
+M.parse_response_without_stream = function(data, _, opts)
+  ---@type OpenAIChatResponse
+  local json = vim.json.decode(data)
+  if json.choices and json.choices[1] then
+    local choice = json.choices[1]
+    if choice.message and choice.message.content then
+      opts.on_chunk(choice.message.content)
+      vim.schedule(function() opts.on_complete(nil) end)
+    end
+  end
+end
+
 M.parse_curl_args = function(provider, code_opts)
   local base, body_opts = P.parse_config(provider)
 
@@ -83,6 +113,14 @@ M.parse_curl_args = function(provider, code_opts)
   }
   if not P.env.is_local("openai") then headers["Authorization"] = "Bearer " .. provider.parse_api_key() end
 
+  -- NOTE: When using "o1" set the supported parameters only
+  local stream = true
+  if base.model and string.find(base.model, "o1") then
+    stream = false
+    body_opts.max_tokens = nil
+    body_opts.temperature = 1
+  end
+
   return {
     url = Utils.trim(base.endpoint, { suffix = "/" }) .. "/chat/completions",
     proxy = base.proxy,
@@ -91,7 +129,7 @@ M.parse_curl_args = function(provider, code_opts)
     body = vim.tbl_deep_extend("force", {
       model = base.model,
       messages = M.parse_message(code_opts),
-      stream = true,
+      stream = stream,
     }, body_opts),
   }
 end