diff --git a/src/__tests__/responses.test.ts b/src/__tests__/responses.test.ts
index 96eb910..abf4947 100644
--- a/src/__tests__/responses.test.ts
+++ b/src/__tests__/responses.test.ts
@@ -1,6 +1,7 @@
 import {
   HttpStatusCodeEnum,
   ResponseErrorPreconditionFailed,
+  ResponseErrorUnauthorized,
   ResponseSuccessJson,
 } from "../responses";
 
@@ -35,6 +36,18 @@ describe("ResponseSuccessJson", () => {
   });
 });
 
+describe("ResponseErrorUnauthorized", () => {
+  const anErrorDetail = "Invalid credentials";
+  it("should return the standard response", () => {
+    expect(ResponseErrorUnauthorized(anErrorDetail)).toMatchObject(
+      expect.objectContaining({
+        kind: "IResponseErrorUnauthorized",
+        detail: `Unauthorized: ${anErrorDetail}`,
+      })
+    );
+  });
+});
+
 describe("ResponseErrorForbiddenNotAuthorized", () => {
   it("should return the standard response", () => {
     expect(getResponseErrorForbiddenNotAuthorized()).toMatchObject(
diff --git a/src/responses.ts b/src/responses.ts
index 1e64e84..a112b8f 100644
--- a/src/responses.ts
+++ b/src/responses.ts
@@ -351,6 +351,27 @@ export const ResponseErrorFromValidationErrors =
     return ResponseErrorValidation(`Invalid ${type.name}`, detail);
   };
 
+/**
+ * Interface for 401 unauthorized
+ */
+export type IResponseErrorUnauthorized =
+  IResponse<"IResponseErrorUnauthorized"> & { readonly detail: string };
+
+/**
+ * Returns an unauthorized error response with status code 401.
+ */
+export const ResponseErrorUnauthorized = (
+  detail: string
+): IResponseErrorUnauthorized => ({
+  ...ResponseErrorGeneric(
+    HttpStatusCodeEnum.HTTP_STATUS_401,
+    "Unauthorized",
+    detail
+  ),
+  detail: `Unauthorized: ${detail}`,
+  kind: "IResponseErrorUnauthorized",
+});
+
 /**
  * The user is not allowed here.
  */