diff --git a/src/api/providers/__tests__/openrouter.spec.ts b/src/api/providers/__tests__/openrouter.spec.ts
index ea850c47be..07246d6982 100644
--- a/src/api/providers/__tests__/openrouter.spec.ts
+++ b/src/api/providers/__tests__/openrouter.spec.ts
@@ -68,6 +68,30 @@ describe("OpenRouterHandler", () => {
 		})
 	})
 
+	it("should warn when API key is missing or invalid", () => {
+		const consoleSpy = vi.spyOn(console, "warn").mockImplementation(() => {})
+
+		// Test with missing API key
+		new OpenRouterHandler({})
+		expect(consoleSpy).toHaveBeenCalledWith(
+			"OpenRouter API key is missing or invalid. This may cause authentication errors.",
+		)
+
+		// Test with empty API key
+		new OpenRouterHandler({ openRouterApiKey: "" })
+		expect(consoleSpy).toHaveBeenCalledWith(
+			"OpenRouter API key is missing or invalid. This may cause authentication errors.",
+		)
+
+		// Test with whitespace-only API key
+		new OpenRouterHandler({ openRouterApiKey: "   " })
+		expect(consoleSpy).toHaveBeenCalledWith(
+			"OpenRouter API key is missing or invalid. This may cause authentication errors.",
+		)
+
+		consoleSpy.mockRestore()
+	})
+
 	describe("fetchModel", () => {
 		it("returns correct model info when options are provided", async () => {
 			const handler = new OpenRouterHandler(mockOptions)
diff --git a/src/api/providers/fetchers/__tests__/openrouter.spec.ts b/src/api/providers/fetchers/__tests__/openrouter.spec.ts
index f0ebead30f..63a13ef4b4 100644
--- a/src/api/providers/fetchers/__tests__/openrouter.spec.ts
+++ b/src/api/providers/fetchers/__tests__/openrouter.spec.ts
@@ -12,6 +12,7 @@ import {
 } from "@roo-code/types"
 
 import { getOpenRouterModelEndpoints, getOpenRouterModels } from "../openrouter"
+import axios from "axios"
 
 nockBack.fixtures = path.join(__dirname, "fixtures")
 nockBack.setMode("lockdown")
@@ -250,5 +251,73 @@ describe("OpenRouter API", () => {
 
 			nockDone()
 		})
+
+		it("should include authorization header when API key is provided", async () => {
+			const mockAxiosGet = vi.spyOn(axios, "get").mockResolvedValue({
+				data: { data: [] },
+			})
+
+			await getOpenRouterModels({ openRouterApiKey: "test-api-key" })
+
+			expect(mockAxiosGet).toHaveBeenCalledWith("https://openrouter.ai/api/v1/models", {
+				headers: { Authorization: "Bearer test-api-key" },
+			})
+
+			mockAxiosGet.mockRestore()
+		})
+
+		it("should not include authorization header when API key is not provided", async () => {
+			const mockAxiosGet = vi.spyOn(axios, "get").mockResolvedValue({
+				data: { data: [] },
+			})
+
+			await getOpenRouterModels()
+
+			expect(mockAxiosGet).toHaveBeenCalledWith("https://openrouter.ai/api/v1/models", { headers: {} })
+
+			mockAxiosGet.mockRestore()
+		})
+
+		it("should throw authentication error on 401 response", async () => {
+			const mockAxiosGet = vi.spyOn(axios, "get").mockRejectedValue({
+				isAxiosError: true,
+				response: { status: 401 },
+			})
+
+			await expect(getOpenRouterModels({ openRouterApiKey: "invalid-key" })).rejects.toThrow(
+				"OpenRouter API authentication failed. Please check your API key.",
+			)
+
+			mockAxiosGet.mockRestore()
+		})
+	})
+
+	describe("getOpenRouterModelEndpoints", () => {
+		it("should include authorization header when API key is provided", async () => {
+			const mockAxiosGet = vi.spyOn(axios, "get").mockResolvedValue({
+				data: { data: { id: "test", name: "test", endpoints: [] } },
+			})
+
+			await getOpenRouterModelEndpoints("test-model", { openRouterApiKey: "test-api-key" })
+
+			expect(mockAxiosGet).toHaveBeenCalledWith("https://openrouter.ai/api/v1/models/test-model/endpoints", {
+				headers: { Authorization: "Bearer test-api-key" },
+			})
+
+			mockAxiosGet.mockRestore()
+		})
+
+		it("should throw authentication error on 401 response", async () => {
+			const mockAxiosGet = vi.spyOn(axios, "get").mockRejectedValue({
+				isAxiosError: true,
+				response: { status: 401 },
+			})
+
+			await expect(
+				getOpenRouterModelEndpoints("test-model", { openRouterApiKey: "invalid-key" }),
+			).rejects.toThrow("OpenRouter API authentication failed. Please check your API key.")
+
+			mockAxiosGet.mockRestore()
+		})
 	})
 })
diff --git a/src/api/providers/fetchers/modelCache.ts b/src/api/providers/fetchers/modelCache.ts
index fef700268d..4fe851653f 100644
--- a/src/api/providers/fetchers/modelCache.ts
+++ b/src/api/providers/fetchers/modelCache.ts
@@ -55,7 +55,10 @@ export const getModels = async (options: GetModelsOptions): Promise<ModelRecord>
 	try {
 		switch (provider) {
 			case "openrouter":
-				models = await getOpenRouterModels()
+				models = await getOpenRouterModels({
+					openRouterApiKey: options.apiKey,
+					openRouterBaseUrl: options.baseUrl,
+				})
 				break
 			case "requesty":
 				// Requesty models endpoint requires an API key for per-user custom policies
diff --git a/src/api/providers/fetchers/openrouter.ts b/src/api/providers/fetchers/openrouter.ts
index 027f8c54fb..58f2a2e0e5 100644
--- a/src/api/providers/fetchers/openrouter.ts
+++ b/src/api/providers/fetchers/openrouter.ts
@@ -97,8 +97,14 @@ export async function getOpenRouterModels(options?: ApiHandlerOptions): Promise<
 	const models: Record<string, ModelInfo> = {}
 	const baseURL = options?.openRouterBaseUrl || "https://openrouter.ai/api/v1"
 
+	// Prepare headers with API key if available
+	const headers: Record<string, string> = {}
+	if (options?.openRouterApiKey) {
+		headers.Authorization = `Bearer ${options.openRouterApiKey}`
+	}
+
 	try {
-		const response = await axios.get<OpenRouterModelsResponse>(`${baseURL}/models`)
+		const response = await axios.get<OpenRouterModelsResponse>(`${baseURL}/models`, { headers })
 		const result = openRouterModelsResponseSchema.safeParse(response.data)
 		const data = result.success ? result.data.data : response.data.data
 
@@ -118,6 +124,10 @@ export async function getOpenRouterModels(options?: ApiHandlerOptions): Promise<
 			})
 		}
 	} catch (error) {
+		if (axios.isAxiosError(error) && error.response?.status === 401) {
+			console.error("OpenRouter API authentication failed. Please check your API key.")
+			throw new Error("OpenRouter API authentication failed. Please check your API key.")
+		}
 		console.error(
 			`Error fetching OpenRouter models: ${JSON.stringify(error, Object.getOwnPropertyNames(error), 2)}`,
 		)
@@ -137,8 +147,16 @@ export async function getOpenRouterModelEndpoints(
 	const models: Record<string, ModelInfo> = {}
 	const baseURL = options?.openRouterBaseUrl || "https://openrouter.ai/api/v1"
 
+	// Prepare headers with API key if available
+	const headers: Record<string, string> = {}
+	if (options?.openRouterApiKey) {
+		headers.Authorization = `Bearer ${options.openRouterApiKey}`
+	}
+
 	try {
-		const response = await axios.get<OpenRouterModelEndpointsResponse>(`${baseURL}/models/${modelId}/endpoints`)
+		const response = await axios.get<OpenRouterModelEndpointsResponse>(`${baseURL}/models/${modelId}/endpoints`, {
+			headers,
+		})
 		const result = openRouterModelEndpointsResponseSchema.safeParse(response.data)
 		const data = result.success ? result.data.data : response.data.data
 
@@ -157,6 +175,10 @@ export async function getOpenRouterModelEndpoints(
 			})
 		}
 	} catch (error) {
+		if (axios.isAxiosError(error) && error.response?.status === 401) {
+			console.error("OpenRouter API authentication failed. Please check your API key.")
+			throw new Error("OpenRouter API authentication failed. Please check your API key.")
+		}
 		console.error(
 			`Error fetching OpenRouter model endpoints: ${JSON.stringify(error, Object.getOwnPropertyNames(error), 2)}`,
 		)
diff --git a/src/api/providers/openrouter.ts b/src/api/providers/openrouter.ts
index 6565daa238..a3cc699295 100644
--- a/src/api/providers/openrouter.ts
+++ b/src/api/providers/openrouter.ts
@@ -66,6 +66,11 @@ export class OpenRouterHandler extends BaseProvider implements SingleCompletionH
 		const baseURL = this.options.openRouterBaseUrl || "https://openrouter.ai/api/v1"
 		const apiKey = this.options.openRouterApiKey ?? "not-provided"
 
+		// Validate API key format
+		if (apiKey === "not-provided" || !apiKey || apiKey.trim() === "") {
+			console.warn("OpenRouter API key is missing or invalid. This may cause authentication errors.")
+		}
+
 		this.client = new OpenAI({ baseURL, apiKey, defaultHeaders: DEFAULT_HEADERS })
 	}
 
@@ -175,11 +180,16 @@ export class OpenRouterHandler extends BaseProvider implements SingleCompletionH
 
 	public async fetchModel() {
 		const [models, endpoints] = await Promise.all([
-			getModels({ provider: "openrouter" }),
+			getModels({
+				provider: "openrouter",
+				apiKey: this.options.openRouterApiKey,
+				baseUrl: this.options.openRouterBaseUrl,
+			}),
 			getModelEndpoints({
 				router: "openrouter",
 				modelId: this.options.openRouterModelId,
 				endpoint: this.options.openRouterSpecificProvider,
+				...this.options,
 			}),
 		])
 
diff --git a/src/shared/api.ts b/src/shared/api.ts
index 8cbfc72133..4a2cd6465f 100644
--- a/src/shared/api.ts
+++ b/src/shared/api.ts
@@ -106,7 +106,7 @@ export const getModelMaxOutputTokens = ({
 // GetModelsOptions
 
 export type GetModelsOptions =
-	| { provider: "openrouter" }
+	| { provider: "openrouter"; apiKey?: string; baseUrl?: string }
 	| { provider: "glama" }
 	| { provider: "requesty"; apiKey?: string }
 	| { provider: "unbound"; apiKey?: string }