diff --git a/package-lock.json b/package-lock.json
index 87ea4958b6..c1e3bdfd36 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -25,7 +25,7 @@
         "@types/jest": "^29.0.0",
         "@types/node": "^22.0.0",
         "esbuild": "^0.24.0",
-        "fetch-mock": "^11.0.0",
+        "fetch-mock": "^12.0.0",
         "glob": "^11.0.0",
         "jest": "^29.0.0",
         "mockdate": "^3.0.5",
@@ -2779,25 +2779,20 @@
       }
     },
     "node_modules/fetch-mock": {
-      "version": "11.1.5",
-      "resolved": "https://registry.npmjs.org/fetch-mock/-/fetch-mock-11.1.5.tgz",
-      "integrity": "sha512-KHmZDnZ1ry0pCTrX4YG5DtThHi0MH+GNI9caESnzX/nMJBrvppUHMvLx47M0WY9oAtKOMiPfZDRpxhlHg89BOA==",
+      "version": "12.2.0",
+      "resolved": "https://registry.npmjs.org/fetch-mock/-/fetch-mock-12.2.0.tgz",
+      "integrity": "sha512-XjgxM582kB0SzPOqH2UdGTwSqga8A8aBPjxcYr0wTeOlCWpZoK6zBrPzltECUTu6Zt3VTWafmKF599LN9BRN5Q==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
         "@types/glob-to-regexp": "^0.4.4",
         "dequal": "^2.0.3",
         "glob-to-regexp": "^0.4.1",
-        "is-subset": "^0.1.1",
+        "is-subset-of": "^3.1.10",
         "regexparam": "^3.0.0"
       },
       "engines": {
-        "node": ">=8.0.0"
-      },
-      "peerDependenciesMeta": {
-        "node-fetch": {
-          "optional": true
-        }
+        "node": ">=18.11.0"
       }
     },
     "node_modules/filelist": {
@@ -3145,12 +3140,16 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/is-subset": {
-      "version": "0.1.1",
-      "resolved": "https://registry.npmjs.org/is-subset/-/is-subset-0.1.1.tgz",
-      "integrity": "sha512-6Ybun0IkarhmEqxXCNw/C0bna6Zb/TkfUX9UbwJtK6ObwAVCxmAP308WWTHviM/zAqXk05cdhYsUsZeGQh99iw==",
+    "node_modules/is-subset-of": {
+      "version": "3.1.10",
+      "resolved": "https://registry.npmjs.org/is-subset-of/-/is-subset-of-3.1.10.tgz",
+      "integrity": "sha512-avvaYgVmYWyaZ1NDFiv4y9JGkrE2je3op1Po4VYKKJKR8H2qVPsg1GZuuXl5elCTxTlwAIsrAjWAs4BVrISFRw==",
+      "deprecated": "Package no longer supported. Contact Support at https://www.npmjs.com/support for more info.",
       "dev": true,
-      "license": "MIT"
+      "license": "MIT",
+      "dependencies": {
+        "typedescriptor": "3.0.2"
+      }
     },
     "node_modules/isexe": {
       "version": "2.0.0",
@@ -5165,6 +5164,14 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/typedescriptor": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/typedescriptor/-/typedescriptor-3.0.2.tgz",
+      "integrity": "sha512-hyVbaCUd18UiXk656g/imaBLMogpdijIEpnhWYrSda9rhvO4gOU16n2nh7xG5lv/rjumnZzGOdz0CEGTmFe0fQ==",
+      "deprecated": "Package no longer supported. Contact Support at https://www.npmjs.com/support for more info.",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/typescript": {
       "version": "5.7.2",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.7.2.tgz",
diff --git a/package.json b/package.json
index 75e73b446b..d92e3ec3b0 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "@types/jest": "^29.0.0",
     "@types/node": "^22.0.0",
     "esbuild": "^0.24.0",
-    "fetch-mock": "^11.0.0",
+    "fetch-mock": "^12.0.0",
     "glob": "^11.0.0",
     "jest": "^29.0.0",
     "mockdate": "^3.0.5",
diff --git a/test/app.test.ts b/test/app.test.ts
index 3b49b460a4..3bffa57ee8 100644
--- a/test/app.test.ts
+++ b/test/app.test.ts
@@ -46,7 +46,7 @@ describe("App", () => {
 
   beforeEach(() => {
     MockDate.set(0);
-    mock = fetchMock.sandbox();
+    mock = fetchMock.createInstance();
 
     app = new App({
       appId: APP_ID,
@@ -60,7 +60,7 @@ describe("App", () => {
       },
       Octokit: Octokit.defaults({
         request: {
-          fetch: mock,
+          fetch: mock.fetchHandler,
         },
         throttle: { enabled: false },
       }),
@@ -128,7 +128,7 @@ describe("App", () => {
       expect(repository.full_name).toEqual("octokit/octokit.js");
     }
 
-    expect(mock.done()).toBe(true);
+    expect(mock.callHistory.done()).toBe(true);
   });
 
   test("README example: app.getInstallationOctokit", async () => {
@@ -167,7 +167,7 @@ describe("App", () => {
       title: "Hello, world!",
     });
 
-    expect(mock.done()).toBe(true);
+    expect(mock.callHistory.done()).toBe(true);
   });
 
   test("README example: createNodeMiddleware(app)", async () => {
@@ -208,7 +208,7 @@ describe("App", () => {
         body: "Hello, World!",
       });
 
-      expect(mock.done()).toBe(true);
+      expect(mock.callHistory.done()).toBe(true);
     });
 
     // Your app can now receive webhook events at `/api/github/webhooks`