diff --git a/packages/jest-cli/src/runGlobalHook.js b/packages/jest-cli/src/runGlobalHook.js
index b779d12c8b58..d51776c4ea3d 100644
--- a/packages/jest-cli/src/runGlobalHook.js
+++ b/packages/jest-cli/src/runGlobalHook.js
@@ -10,12 +10,12 @@
 import type {GlobalConfig} from 'types/Config';
 import type {Test} from 'types/TestRunner';
 
-import {extname, resolve} from 'path';
+import {extname, resolve, sep} from 'path';
 import pEachSeries from 'p-each-series';
 import {addHook} from 'pirates';
 import {ScriptTransformer} from 'jest-runtime';
 
-const inJestsSource = __dirname.includes('packages/jest-cli');
+const inJestsSource = __dirname.includes(`packages${sep}jest-cli`);
 let packagesRoot;
 
 if (inJestsSource) {