diff --git a/packages/mock/src/msw/index.test.ts b/packages/mock/src/msw/index.test.ts
new file mode 100644
index 000000000..6c95735fb
--- /dev/null
+++ b/packages/mock/src/msw/index.test.ts
@@ -0,0 +1,116 @@
+import type { GeneratorOptions, GeneratorVerbOptions } from '@orval/core';
+import { describe, expect, it } from 'vitest';
+
+import { generateMSW } from './index';
+
+describe('generateMSW', () => {
+  const mockVerbOptions: GeneratorVerbOptions = {
+    operationId: 'getUser',
+    verb: 'get',
+    tags: [],
+    response: {
+      imports: [],
+      definition: { success: 'User' },
+      types: { success: [{ key: '200', value: 'User' }] },
+      contentTypes: ['application/json'],
+    },
+  } as GeneratorVerbOptions;
+
+  const baseOptions: GeneratorOptions = {
+    pathRoute: '/users/{id}',
+    override: { operations: {}, tags: {} },
+    context: {
+      specKey: 'test',
+      specs: { test: {} },
+      output: { override: {} },
+    },
+  } as GeneratorOptions;
+
+  const generate = (overrides: Partial<GeneratorOptions> = {}) =>
+    generateMSW(mockVerbOptions, { ...baseOptions, ...overrides });
+
+  describe('delay functionality', () => {
+    it('should not include delay call when no delay is provided', () => {
+      const result = generate();
+      expect(result.implementation.handler).not.toContain('await delay');
+    });
+
+    it('should include delay call when delay is a number', () => {
+      const result = generate({ mock: { delay: 100 } });
+      expect(result.implementation.handler).toContain('await delay(100);');
+    });
+
+    it('should not include delay call when delay is false', () => {
+      const result = generate({ mock: { delay: false } });
+      expect(result.implementation.handler).not.toContain('await delay');
+    });
+
+    it('should execute delay function immediately when delayFunctionLazyExecute is false', () => {
+      const result = generate({
+        mock: { delay: () => 200, delayFunctionLazyExecute: false },
+      });
+      expect(result.implementation.handler).toContain('await delay(200);');
+    });
+
+    it('should preserve delay function when delayFunctionLazyExecute is true', () => {
+      const result = generate({
+        mock: {
+          delay: () => Number(process.env.MSW_DELAY) || 10,
+          delayFunctionLazyExecute: true,
+        },
+      });
+      expect(result.implementation.handler).toContain(
+        'await delay((() => Number(process.env.MSW_DELAY) || 10)());',
+      );
+    });
+
+    it('should handle delay function in override.mock', () => {
+      const result = generate({
+        override: {
+          ...baseOptions.override,
+          mock: { delay: () => 300, delayFunctionLazyExecute: true },
+        },
+      });
+      expect(result.implementation.handler).toContain(
+        'await delay((() => 300)());',
+      );
+    });
+
+    it('should prioritize override.mock.delay over options.mock.delay', () => {
+      const result = generate({
+        mock: { delay: 100 },
+        override: { ...baseOptions.override, mock: { delay: 500 } },
+      });
+      expect(result.implementation.handler).toContain('await delay(500);');
+      expect(result.implementation.handler).not.toContain('await delay(100);');
+    });
+
+    it('should prioritize override.mock.delayFunctionLazyExecute', () => {
+      const result = generate({
+        mock: { delay: () => 100, delayFunctionLazyExecute: false },
+        override: {
+          ...baseOptions.override,
+          mock: { delay: () => 200, delayFunctionLazyExecute: true },
+        },
+      });
+      expect(result.implementation.handler).toContain(
+        'await delay((() => 200)());',
+      );
+    });
+  });
+
+  describe('handler generation', () => {
+    it('should generate a valid MSW handler', () => {
+      const result = generate({ mock: { delay: 100 } });
+
+      expect(result.implementation.handlerName).toBe('getGetUserMockHandler');
+      expect(result.implementation.handler).toContain(
+        'export const getGetUserMockHandler',
+      );
+      expect(result.implementation.handler).toContain('return http.get');
+      expect(result.implementation.handler).toContain(
+        'return new HttpResponse',
+      );
+    });
+  });
+});
diff --git a/packages/mock/src/msw/index.ts b/packages/mock/src/msw/index.ts
index 5b19917e1..34d0a665a 100644
--- a/packages/mock/src/msw/index.ts
+++ b/packages/mock/src/msw/index.ts
@@ -134,7 +134,9 @@ const generateDefinition = (
   const handlerImplementation = `
 export const ${handlerName} = (overrideResponse?: ${returnType} | ((${infoParam}: Parameters<Parameters<typeof http.${verb}>[1]>[0]) => Promise<${returnType}> | ${returnType}), options?: RequestHandlerOptions) => {
   return http.${verb}('${route}', async (${infoParam}) => {${
-    typeof delay === 'number' ? `await delay(${delay});` : ''
+    delay === false
+      ? ''
+      : `await delay(${isFunction(delay) ? `(${delay})()` : delay});`
   }
   ${isReturnHttpResponse ? '' : `if (typeof overrideResponse === 'function') {await overrideResponse(info); }`}
     return new HttpResponse(${