diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java
index e4ea5e4010c..06ae93b2531 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java
@@ -1139,7 +1139,7 @@ public record ChatCompletionRequest(// @formatter:off
 			@JsonProperty("verbosity") String verbosity,
 			@JsonProperty("prompt_cache_key") String promptCacheKey,
 			@JsonProperty("safety_identifier") String safetyIdentifier,
-			Map<String, Object> extraBody) {
+			@JsonProperty("extra_body") Map<String, Object> extraBody) {
 
 		/**
 		 * Compact constructor that ensures extraBody is initialized as a mutable HashMap
diff --git a/models/spring-ai-openai/src/test/java/org/springframework/ai/openai/ChatCompletionRequestTests.java b/models/spring-ai-openai/src/test/java/org/springframework/ai/openai/ChatCompletionRequestTests.java
index 3d7623c96f4..9f600c8745e 100644
--- a/models/spring-ai-openai/src/test/java/org/springframework/ai/openai/ChatCompletionRequestTests.java
+++ b/models/spring-ai-openai/src/test/java/org/springframework/ai/openai/ChatCompletionRequestTests.java
@@ -76,9 +76,13 @@ void whenToolRuntimeOptionsThenMergeWithDefaults() {
 	@Test
 	void createRequestWithChatOptions() {
 		var client = OpenAiChatModel.builder()
-			.openAiApi(OpenAiApi.builder().apiKey("TEST").build())
-			.defaultOptions(OpenAiChatOptions.builder().model("DEFAULT_MODEL").temperature(66.6).build())
-			.build();
+				.openAiApi(OpenAiApi.builder().apiKey("TEST").build())
+				.defaultOptions(OpenAiChatOptions.builder()
+						.model("DEFAULT_MODEL")
+						.temperature(66.6)
+						.extraBody(Map.of("key1", "value1"))
+						.build())
+				.build();
 
 		var prompt = client.buildRequestPrompt(new Prompt("Test message content"));
 
@@ -90,6 +94,8 @@ void createRequestWithChatOptions() {
 		assertThat(request.model()).isEqualTo("DEFAULT_MODEL");
 		assertThat(request.temperature()).isEqualTo(66.6);
 
+		assertThat(request.extraBody().get("key1")).isEqualTo("value1");
+
 		request = client.createRequest(new Prompt("Test message content",
 				OpenAiChatOptions.builder().model("PROMPT_MODEL").temperature(99.9).build()), true);