diff --git a/.changeset/gpt5-support.md b/.changeset/gpt5-support.md
new file mode 100644
index 0000000000..173d60899c
--- /dev/null
+++ b/.changeset/gpt5-support.md
@@ -0,0 +1,11 @@
+---
+"@roo-code/types": minor
+"roo-cline": minor
+---
+
+Add GPT-5 model support
+
+- Added GPT-5 models (gpt-5-2025-08-07, gpt-5-mini-2025-08-07, gpt-5-nano-2025-08-07) to OpenAI Native provider
+- Added nectarine-alpha-new-reasoning-effort-2025-07-25 experimental model
+- Set gpt-5-2025-08-07 as the new default OpenAI Native model
+- Implemented GPT-5 specific handling with streaming and reasoning effort support
diff --git a/packages/types/src/providers/openai.ts b/packages/types/src/providers/openai.ts
index 0afdd46feb..027ee17f1a 100644
--- a/packages/types/src/providers/openai.ts
+++ b/packages/types/src/providers/openai.ts
@@ -3,9 +3,45 @@ import type { ModelInfo } from "../model.js"
 // https://openai.com/api/pricing/
 export type OpenAiNativeModelId = keyof typeof openAiNativeModels
 
-export const openAiNativeDefaultModelId: OpenAiNativeModelId = "gpt-4.1"
+export const openAiNativeDefaultModelId: OpenAiNativeModelId = "gpt-5-2025-08-07"
 
 export const openAiNativeModels = {
+	"gpt-5-2025-08-07": {
+		maxTokens: 128000,
+		contextWindow: 256000,
+		supportsImages: true,
+		supportsPromptCache: true,
+		inputPrice: 1.25,
+		outputPrice: 10.0,
+		cacheReadsPrice: 0.125,
+	},
+	"gpt-5-mini-2025-08-07": {
+		maxTokens: 128000,
+		contextWindow: 256000,
+		supportsImages: true,
+		supportsPromptCache: true,
+		inputPrice: 0.25,
+		outputPrice: 2.0,
+		cacheReadsPrice: 0.025,
+	},
+	"gpt-5-nano-2025-08-07": {
+		maxTokens: 128000,
+		contextWindow: 256000,
+		supportsImages: true,
+		supportsPromptCache: true,
+		inputPrice: 0.05,
+		outputPrice: 0.4,
+		cacheReadsPrice: 0.005,
+	},
+	"nectarine-alpha-new-reasoning-effort-2025-07-25": {
+		maxTokens: 128000,
+		contextWindow: 256000,
+		supportsImages: true,
+		supportsPromptCache: true,
+		inputPrice: 0,
+		outputPrice: 0,
+		cacheReadsPrice: 0,
+	},
 	"gpt-4.1": {
 		maxTokens: 32_768,
 		contextWindow: 1_047_576,
diff --git a/src/api/providers/openai-native.ts b/src/api/providers/openai-native.ts
index 3f14e65cc6..c9913406a5 100644
--- a/src/api/providers/openai-native.ts
+++ b/src/api/providers/openai-native.ts
@@ -53,6 +53,8 @@ export class OpenAiNativeHandler extends BaseProvider implements SingleCompletio
 			yield* this.handleReasonerMessage(model, id, systemPrompt, messages)
 		} else if (model.id.startsWith("o1")) {
 			yield* this.handleO1FamilyMessage(model, systemPrompt, messages)
+		} else if (this.isGPT5Model(model.id)) {
+			yield* this.handleGPT5Message(model, systemPrompt, messages)
 		} else {
 			yield* this.handleDefaultModelMessage(model, systemPrompt, messages)
 		}
@@ -123,6 +125,26 @@ export class OpenAiNativeHandler extends BaseProvider implements SingleCompletio
 		yield* this.handleStreamResponse(stream, model)
 	}
 
+	private async *handleGPT5Message(
+		model: OpenAiNativeModel,
+		systemPrompt: string,
+		messages: Anthropic.Messages.MessageParam[],
+	): ApiStream {
+		const stream = await this.client.chat.completions.create({
+			model: model.id,
+			temperature: 1,
+			messages: [{ role: "developer", content: systemPrompt }, ...convertToOpenAiMessages(messages)],
+			stream: true,
+			stream_options: { include_usage: true },
+		})
+
+		yield* this.handleStreamResponse(stream, model)
+	}
+
+	private isGPT5Model(modelId: string): boolean {
+		return modelId.includes("gpt-5") || modelId.includes("gpt5") || modelId.includes("nectarine")
+	}
+
 	private async *handleStreamResponse(
 		stream: AsyncIterable<OpenAI.Chat.Completions.ChatCompletionChunk>,
 		model: OpenAiNativeModel,