diff --git a/chat.go b/chat.go
index d47c95e4..46395f35 100644
--- a/chat.go
+++ b/chat.go
@@ -207,9 +207,9 @@ type ChatCompletionRequest struct {
 	// This value is now deprecated in favor of max_completion_tokens, and is not compatible with o1 series models.
 	// refs: https://platform.openai.com/docs/api-reference/chat/create#chat-create-max_tokens
 	MaxTokens int `json:"max_tokens,omitempty"`
-	// MaxCompletionsTokens An upper bound for the number of tokens that can be generated for a completion,
+	// MaxCompletionTokens An upper bound for the number of tokens that can be generated for a completion,
 	// including visible output tokens and reasoning tokens https://platform.openai.com/docs/guides/reasoning
-	MaxCompletionsTokens int                           `json:"max_completions_tokens,omitempty"`
+	MaxCompletionTokens int                           `json:"max_completion_tokens,omitempty"`
 	Temperature          float32                       `json:"temperature,omitempty"`
 	TopP                 float32                       `json:"top_p,omitempty"`
 	N                    int                           `json:"n,omitempty"`
diff --git a/chat_test.go b/chat_test.go
index a54dd35e..93ac3554 100644
--- a/chat_test.go
+++ b/chat_test.go
@@ -100,7 +100,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "log_probs_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				LogProbs:             true,
 				Model:                openai.O1Preview,
 			},
@@ -109,7 +109,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "message_type_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				Model:                openai.O1Mini,
 				Messages: []openai.ChatCompletionMessage{
 					{
@@ -122,7 +122,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "tool_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				Model:                openai.O1Mini,
 				Messages: []openai.ChatCompletionMessage{
 					{
@@ -143,7 +143,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "set_temperature_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				Model:                openai.O1Mini,
 				Messages: []openai.ChatCompletionMessage{
 					{
@@ -160,7 +160,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "set_top_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				Model:                openai.O1Mini,
 				Messages: []openai.ChatCompletionMessage{
 					{
@@ -178,7 +178,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "set_n_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				Model:                openai.O1Mini,
 				Messages: []openai.ChatCompletionMessage{
 					{
@@ -197,7 +197,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "set_presence_penalty_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				Model:                openai.O1Mini,
 				Messages: []openai.ChatCompletionMessage{
 					{
@@ -214,7 +214,7 @@ func TestO1ModelsChatCompletionsBetaLimitations(t *testing.T) {
 		{
 			name: "set_frequency_penalty_unsupported",
 			in: openai.ChatCompletionRequest{
-				MaxCompletionsTokens: 1000,
+				MaxCompletionTokens: 1000,
 				Model:                openai.O1Mini,
 				Messages: []openai.ChatCompletionMessage{
 					{
@@ -297,7 +297,7 @@ func TestO1ModelChatCompletions(t *testing.T) {
 	server.RegisterHandler("/v1/chat/completions", handleChatCompletionEndpoint)
 	_, err := client.CreateChatCompletion(context.Background(), openai.ChatCompletionRequest{
 		Model:                openai.O1Preview,
-		MaxCompletionsTokens: 1000,
+		MaxCompletionTokens: 1000,
 		Messages: []openai.ChatCompletionMessage{
 			{
 				Role:    openai.ChatMessageRoleUser,
diff --git a/completion.go b/completion.go
index 8e3172ac..5a154f82 100644
--- a/completion.go
+++ b/completion.go
@@ -7,7 +7,7 @@ import (
 )
 
 var (
-	ErrO1MaxTokensDeprecated                   = errors.New("this model is not supported MaxTokens, please use MaxCompletionsTokens")                              //nolint:lll
+	ErrO1MaxTokensDeprecated                   = errors.New("this model is not supported MaxTokens, please use MaxCompletionTokens")                              //nolint:lll
 	ErrCompletionUnsupportedModel              = errors.New("this model is not supported with this method, please use CreateChatCompletion client method instead") //nolint:lll
 	ErrCompletionStreamNotSupported            = errors.New("streaming is not supported with this method, please use CreateCompletionStream")                      //nolint:lll
 	ErrCompletionRequestPromptTypeNotSupported = errors.New("the type of CompletionRequest.Prompt only supports string and []string")                              //nolint:lll