diff --git a/CHANGELOG.md b/CHANGELOG.md
index f927a86cc696..d405037f342a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@
 
 - `[*]` Replace `any`s with `unknown`s ([#9626](https://github.com/facebook/jest/pull/9626))
 - `[@jest/transform]` Expose type `CacheKeyOptions` for `getCacheKey` ([#9762](https://github.com/facebook/jest/pull/9762))
+- `[@jest/types]` Correct type `testRegex` for `ProjectConfig` ([#9780](https://github.com/facebook/jest/pull/9780))
 
 ### Performance
 
diff --git a/packages/jest-core/src/SearchSource.ts b/packages/jest-core/src/SearchSource.ts
index a2b30f8b2652..7a2c6a863cc6 100644
--- a/packages/jest-core/src/SearchSource.ts
+++ b/packages/jest-core/src/SearchSource.ts
@@ -40,8 +40,9 @@ export type TestSelectionConfig = {
 const globsToMatcher = (globs: Array<Config.Glob>) => (path: Config.Path) =>
   micromatch([replacePathSepForGlob(path)], globs, {dot: true}).length > 0;
 
-const regexToMatcher = (testRegex: Array<string>) => (path: Config.Path) =>
-  testRegex.some(testRegex => new RegExp(testRegex).test(path));
+const regexToMatcher = (testRegex: Config.ProjectConfig['testRegex']) => (
+  path: Config.Path,
+) => testRegex.some(testRegex => new RegExp(testRegex).test(path));
 
 const toTests = (context: Context, tests: Array<Config.Path>) =>
   tests.map(path => ({
diff --git a/packages/jest-types/src/Config.ts b/packages/jest-types/src/Config.ts
index 7169f8e13f18..6c5ab99f1a26 100644
--- a/packages/jest-types/src/Config.ts
+++ b/packages/jest-types/src/Config.ts
@@ -345,7 +345,7 @@ export type ProjectConfig = {
   testMatch: Array<Glob>;
   testLocationInResults: boolean;
   testPathIgnorePatterns: Array<string>;
-  testRegex: Array<string>;
+  testRegex: Array<string | RegExp>;
   testRunner: string;
   testURL: string;
   timers: 'real' | 'fake';