diff --git a/packages/react-native/scripts/hermes/hermes-utils.js b/packages/react-native/scripts/hermes/hermes-utils.js
index 5ee9f73e624cbe..3a5aa8dcb3388f 100644
--- a/packages/react-native/scripts/hermes/hermes-utils.js
+++ b/packages/react-native/scripts/hermes/hermes-utils.js
@@ -4,6 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
@@ -14,6 +15,10 @@ const fs = require('fs');
 const os = require('os');
 const path = require('path');
 
+/*::
+type BuildType = 'dry-run' | 'release' | 'nightly' | 'prealpha';
+*/
+
 const SDKS_DIR = path.normalize(path.join(__dirname, '..', '..', 'sdks'));
 const HERMES_DIR = path.join(SDKS_DIR, 'hermes');
 const HERMES_TAG_FILE_PATH = path.join(SDKS_DIR, '.hermesversion');
@@ -34,11 +39,15 @@ const MACOS_IMPORT_HERMESC_PATH = path.join(
  * @param args Array of arguments pass to the command.
  * @param options child process options.
  */
-function delegateSync(command, args, options) {
+function delegateSync(
+  command /*: string */,
+  args /*: (Array<string> | child_process$spawnSyncOpts) */,
+  options /*: ?child_process$spawnSyncOpts */,
+) {
   return spawnSync(command, args, {stdio: 'inherit', ...options});
 }
 
-function readHermesTag() {
+function readHermesTag() /*: string */ {
   if (fs.existsSync(HERMES_TAG_FILE_PATH)) {
     const data = fs
       .readFileSync(HERMES_TAG_FILE_PATH, {
@@ -57,7 +66,7 @@ function readHermesTag() {
   return 'main';
 }
 
-function setHermesTag(hermesTag) {
+function setHermesTag(hermesTag /*: string */) {
   if (readHermesTag() === hermesTag) {
     // No need to update.
     return;
@@ -70,7 +79,7 @@ function setHermesTag(hermesTag) {
   console.log('Hermes tag has been updated. Please commit your changes.');
 }
 
-function getHermesTagSHA(hermesTag) {
+function getHermesTagSHA(hermesTag /*: string */) /*: string */ {
   return execSync(
     `git ls-remote https://github.com/facebook/hermes ${hermesTag} | cut -f 1`,
   )
@@ -78,7 +87,7 @@ function getHermesTagSHA(hermesTag) {
     .trim();
 }
 
-function getHermesTarballDownloadPath(hermesTag) {
+function getHermesTarballDownloadPath(hermesTag /*: string */) /*: string */ {
   const hermesTagSHA = getHermesTagSHA(hermesTag);
   return path.join(HERMES_TARBALL_DOWNLOAD_DIR, `hermes-${hermesTagSHA}.tgz`);
 }
@@ -184,11 +193,13 @@ function isTestingAgainstLocalHermesTarball() {
   return 'HERMES_ENGINE_TARBALL_PATH' in process.env;
 }
 
-function shouldBuildHermesFromSource(isInCI) {
+function shouldBuildHermesFromSource(isInCI /*: boolean */) /*: boolean */ {
   return !isTestingAgainstLocalHermesTarball() && isInCI;
 }
 
-function shouldUsePrebuiltHermesC(platform) {
+function shouldUsePrebuiltHermesC(
+  platform /*: 'macos' | 'windows' */,
+) /*: boolean */ {
   if (platform === 'macos') {
     return fs.existsSync(MACOS_HERMESC_PATH);
   }
@@ -212,7 +223,9 @@ set_target_properties(native-hermesc PROPERTIES
   }
 }
 
-function getHermesPrebuiltArtifactsTarballName(buildType) {
+function getHermesPrebuiltArtifactsTarballName(
+  buildType /*: string */,
+) /*: string */ {
   if (!buildType) {
     throw Error('Did not specify build type.');
   }
@@ -222,17 +235,20 @@ function getHermesPrebuiltArtifactsTarballName(buildType) {
 /**
  * Creates a tarball with the contents of the supplied directory.
  */
-function createTarballFromDirectory(directory, filename) {
+function createTarballFromDirectory(
+  directory /*: string */,
+  filename /*: string */,
+) {
   const args = ['-C', directory, '-czvf', filename, '.'];
   delegateSync('tar', args);
 }
 
 function createHermesPrebuiltArtifactsTarball(
-  hermesDir,
-  buildType,
-  tarballOutputDir,
-  excludeDebugSymbols,
-) {
+  hermesDir /*: string */,
+  buildType /*: string */,
+  tarballOutputDir /*: string */,
+  excludeDebugSymbols /*: boolean */,
+) /*: string */ {
   validateHermesFrameworksExist(path.join(hermesDir, 'destroot'));
 
   if (!fs.existsSync(tarballOutputDir)) {
@@ -282,7 +298,7 @@ function createHermesPrebuiltArtifactsTarball(
   return tarballFilename;
 }
 
-function validateHermesFrameworksExist(destrootDir) {
+function validateHermesFrameworksExist(destrootDir /*: string */) {
   if (
     !fs.existsSync(
       path.join(destrootDir, 'Library/Frameworks/macosx/hermes.framework'),
diff --git a/scripts/release-utils.js b/scripts/release-utils.js
index d31b5c81b19539..3f6fcabb839590 100644
--- a/scripts/release-utils.js
+++ b/scripts/release-utils.js
@@ -4,6 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
@@ -14,7 +15,11 @@ const {
 } = require('../packages/react-native/scripts/hermes/hermes-utils');
 const {echo, env, exec, exit, popd, pushd, test} = require('shelljs');
 
-function generateAndroidArtifacts(releaseVersion) {
+/*::
+type BuildType = 'dry-run' | 'release' | 'nightly' | 'prealpha';
+*/
+
+function generateAndroidArtifacts(releaseVersion /*: string */) {
   // -------- Generating Android Artifacts
   echo('Generating Android artifacts inside /tmp/maven-local');
   if (exec('./gradlew publishAllToMavenTempLocal').code) {
@@ -52,10 +57,15 @@ function generateAndroidArtifacts(releaseVersion) {
   });
 }
 
-function publishAndroidArtifactsToMaven(releaseVersion, buildType) {
+function publishAndroidArtifactsToMaven(
+  releaseVersion /*: string */,
+  buildType /*: BuildType */,
+) {
   // -------- Publish every artifact to Maven Central
   // The GPG key is base64 encoded on CircleCI and then decoded here
+  // $FlowFixMe[prop-missing]
   let buff = Buffer.from(env.ORG_GRADLE_PROJECT_SIGNING_KEY_ENCODED, 'base64');
+  // $FlowFixMe[prop-missing]
   env.ORG_GRADLE_PROJECT_SIGNING_KEY = buff.toString('ascii');
 
   // We want to gate ourselves against accidentally publishing a 1.x or a 1000.x on
@@ -76,7 +86,9 @@ function publishAndroidArtifactsToMaven(releaseVersion, buildType) {
     const isSnapshot = buildType === 'nightly' || buildType === 'prealpha';
     // -------- For nightly releases, we only need to publish the snapshot to Sonatype snapshot repo.
     if (
-      exec('./gradlew publishAllToSonatype -PisSnapshot=' + isSnapshot).code
+      exec(
+        './gradlew publishAllToSonatype -PisSnapshot=' + isSnapshot.toString(),
+      ).code
     ) {
       echo('Failed to publish artifacts to Sonatype (Maven Central)');
       exit(1);
@@ -87,11 +99,11 @@ function publishAndroidArtifactsToMaven(releaseVersion, buildType) {
 }
 
 function generateiOSArtifacts(
-  jsiFolder,
-  hermesCoreSourceFolder,
-  buildType,
-  targetFolder,
-) {
+  jsiFolder /*: string */,
+  hermesCoreSourceFolder /*: string */,
+  buildType /*: 'Debug' | string */,
+  targetFolder /*: string */,
+) /*: string */ {
   pushd(`${hermesCoreSourceFolder}`);
 
   //Generating iOS Artifacts
@@ -115,7 +127,7 @@ function generateiOSArtifacts(
   return tarballOutputPath;
 }
 
-function failIfTagExists(version, buildType) {
+function failIfTagExists(version /*: string */, buildType /*: BuildType */) {
   // When dry-run in stable branch, the tag already exists.
   // We are bypassing the tag-existence check when in a dry-run to have the CI pass
   if (buildType === 'dry-run') {
@@ -130,7 +142,7 @@ function failIfTagExists(version, buildType) {
   }
 }
 
-function checkIfTagExists(version) {
+function checkIfTagExists(version /*: string */) {
   const {code, stdout} = exec('git tag -l', {silent: true});
   if (code !== 0) {
     throw new Error('Failed to retrieve the list of tags');
diff --git a/scripts/test-e2e-local-clean.js b/scripts/test-e2e-local-clean.js
index b86a8a43b23445..896e8b9fc6a9f6 100644
--- a/scripts/test-e2e-local-clean.js
+++ b/scripts/test-e2e-local-clean.js
@@ -4,6 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
diff --git a/scripts/test-e2e-local.js b/scripts/test-e2e-local.js
index a8938751a402f9..a20c093ddcd6ea 100644
--- a/scripts/test-e2e-local.js
+++ b/scripts/test-e2e-local.js
@@ -4,6 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
@@ -28,6 +29,10 @@ const path = require('path');
 const {cd, exec, popd, pushd, pwd, sed} = require('shelljs');
 const yargs = require('yargs');
 
+/* ::
+type Unwrap<T> = T extends Promise<infer U> ? U : T;
+*/
+
 const argv = yargs
   .option('t', {
     alias: 'target',
@@ -59,17 +64,20 @@ const argv = yargs
  * - @circleCIArtifacts manager object to manage all the download of CircleCIArtifacts. If null, it will fallback not to use them.
  * - @onReleaseBranch whether we are on a release branch or not
  */
-async function testRNTesterIOS(circleCIArtifacts, onReleaseBranch) {
+async function testRNTesterIOS(
+  circleCIArtifacts /*: Unwrap<ReturnType<typeof setupCircleCIArtifacts>> */,
+  onReleaseBranch /*: boolean */,
+) {
   console.info(
     `We're going to test the ${
-      argv.hermes ? 'Hermes' : 'JSC'
+      argv.hermes === true ? 'Hermes' : 'JSC'
     } version of RNTester iOS with the new Architecture enabled`,
   );
 
   // remember that for this to be successful
   // you should have run bundle install once
   // in your local setup
-  if (argv.hermes && circleCIArtifacts != null) {
+  if (argv.hermes === true && circleCIArtifacts != null) {
     const hermesURL = await circleCIArtifacts.artifactURLHermesDebug();
     const hermesPath = path.join(
       circleCIArtifacts.baseTmpPath(),
@@ -84,14 +92,14 @@ async function testRNTesterIOS(circleCIArtifacts, onReleaseBranch) {
   } else {
     exec(
       `USE_HERMES=${
-        argv.hermes ? 1 : 0
-      } CI=${onReleaseBranch} RCT_NEW_ARCH_ENABLED=1 bundle exec pod install --ansi`,
+        argv.hermes === true ? 1 : 0
+      } CI=${onReleaseBranch.toString()} RCT_NEW_ARCH_ENABLED=1 bundle exec pod install --ansi`,
     );
   }
 
   // if everything succeeded so far, we can launch Metro and the app
   // start the Metro server in a separate window
-  launchPackagerInSeparateWindow(pwd());
+  launchPackagerInSeparateWindow(pwd().toString());
 
   // launch the app on iOS simulator
   exec('npx react-native run-ios --scheme RNTester --simulator "iPhone 14"');
@@ -103,17 +111,19 @@ async function testRNTesterIOS(circleCIArtifacts, onReleaseBranch) {
  * Parameters:
  * - @circleCIArtifacts manager object to manage all the download of CircleCIArtifacts. If null, it will fallback not to use them.
  */
-async function testRNTesterAndroid(circleCIArtifacts) {
+async function testRNTesterAndroid(
+  circleCIArtifacts /*: Unwrap<ReturnType<typeof setupCircleCIArtifacts>> */,
+) {
   maybeLaunchAndroidEmulator();
 
   console.info(
     `We're going to test the ${
-      argv.hermes ? 'Hermes' : 'JSC'
+      argv.hermes === true ? 'Hermes' : 'JSC'
     } version of RNTester Android with the new Architecture enabled`,
   );
 
   // Start the Metro server so it will be ready if the app can be built and installed successfully.
-  launchPackagerInSeparateWindow(pwd());
+  launchPackagerInSeparateWindow(pwd().toString());
 
   // Wait for the Android Emulator to be properly loaded and bootstrapped
   exec(
@@ -127,9 +137,10 @@ async function testRNTesterAndroid(circleCIArtifacts) {
     );
 
     const emulatorArch = exec('adb shell getprop ro.product.cpu.abi').trim();
-    const rntesterAPKURL = argv.hermes
-      ? await circleCIArtifacts.artifactURLForHermesRNTesterAPK(emulatorArch)
-      : await circleCIArtifacts.artifactURLForJSCRNTesterAPK(emulatorArch);
+    const rntesterAPKURL =
+      argv.hermes === true
+        ? await circleCIArtifacts.artifactURLForHermesRNTesterAPK(emulatorArch)
+        : await circleCIArtifacts.artifactURLForJSCRNTesterAPK(emulatorArch);
 
     console.info('Start Downloading APK');
     circleCIArtifacts.downloadArtifact(rntesterAPKURL, downloadPath);
@@ -138,7 +149,7 @@ async function testRNTesterAndroid(circleCIArtifacts) {
   } else {
     exec(
       `../../gradlew :packages:rn-tester:android:app:${
-        argv.hermes ? 'installHermesDebug' : 'installJscDebug'
+        argv.hermes === true ? 'installHermesDebug' : 'installJscDebug'
       } --quiet`,
     );
   }
@@ -161,7 +172,10 @@ async function testRNTesterAndroid(circleCIArtifacts) {
  * - @circleCIArtifacts manager object to manage all the download of CircleCIArtifacts. If null, it will fallback not to use them.
  * - @onReleaseBranch whether we are on a release branch or not
  */
-async function testRNTester(circleCIArtifacts, onReleaseBranch) {
+async function testRNTester(
+  circleCIArtifacts /*:Unwrap<ReturnType<typeof setupCircleCIArtifacts>> */,
+  onReleaseBranch /*: boolean */,
+) {
   // FIXME: make sure that the commands retains colors
   // (--ansi) doesn't always work
   // see also https://github.com/shelljs/shelljs/issues/86
@@ -177,7 +191,9 @@ async function testRNTester(circleCIArtifacts, onReleaseBranch) {
 
 // === RNTestProject === //
 
-async function testRNTestProject(circleCIArtifacts) {
+async function testRNTestProject(
+  circleCIArtifacts /*: Unwrap<ReturnType<typeof setupCircleCIArtifacts>> */,
+) {
   console.info("We're going to test a fresh new RN project");
 
   // create the local npm package to feed the CLI
@@ -195,7 +211,7 @@ async function testRNTestProject(circleCIArtifacts) {
   const buildType = 'dry-run';
 
   // Prepare some variables for later use
-  const repoRoot = pwd();
+  const repoRoot = pwd().toString();
   const reactNativePackagePath = `${repoRoot}/packages/react-native`;
   const localNodeTGZPath = `${reactNativePackagePath}/react-native-${releaseVersion}.tgz`;
 
@@ -239,7 +255,7 @@ async function testRNTestProject(circleCIArtifacts) {
   );
 
   // Update gradle properties to set Hermes as false
-  if (!argv.hermes) {
+  if (argv.hermes == null) {
     sed(
       '-i',
       'hermesEnabled=true',
@@ -254,7 +270,7 @@ async function testRNTestProject(circleCIArtifacts) {
     exec('bundle install');
     exec(
       `HERMES_ENGINE_TARBALL_PATH=${hermesPath} USE_HERMES=${
-        argv.hermes ? 1 : 0
+        argv.hermes === true ? 1 : 0
       } bundle exec pod install --ansi`,
     );
 
@@ -286,7 +302,8 @@ async function main() {
   const onReleaseBranch = branchName.endsWith('-stable');
 
   let circleCIArtifacts = await setupCircleCIArtifacts(
-    argv.circleciToken,
+    // $FlowIgnoreError[prop-missing]
+    argv.circleCIToken,
     branchName,
   );
 
@@ -297,4 +314,5 @@ async function main() {
   }
 }
 
+// $FlowIgnoreError[unused-promise]
 main();
diff --git a/scripts/testing-utils.js b/scripts/testing-utils.js
index 8588a9bba164b3..0e789980e2af05 100644
--- a/scripts/testing-utils.js
+++ b/scripts/testing-utils.js
@@ -4,6 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
@@ -19,11 +20,16 @@ const {
   generateiOSArtifacts,
 } = require('./release-utils');
 const fs = require('fs');
+// $FlowIgnore[cannot-resolve-module]
 const {spawn} = require('node:child_process');
 const os = require('os');
 const path = require('path');
 const {cp, exec} = require('shelljs');
 
+/*::
+type BuildType = 'dry-run' | 'release' | 'nightly' | 'prealpha';
+*/
+
 /*
  * Android related utils - leverages android tooling
  */
@@ -32,24 +38,29 @@ const {cp, exec} = require('shelljs');
 // here's the reference folder:
 // https://github.com/react-native-community/cli/blob/main/packages/cli-platform-android/src/commands/runAndroid
 
-const emulatorCommand = process.env.ANDROID_HOME
-  ? `${process.env.ANDROID_HOME}/emulator/emulator`
-  : 'emulator';
+const emulatorCommand =
+  process.env.ANDROID_HOME != null
+    ? `${process.env.ANDROID_HOME}/emulator/emulator`
+    : 'emulator';
 
 const getEmulators = () => {
   const emulatorsOutput = exec(`${emulatorCommand} -list-avds`).stdout;
   return emulatorsOutput.split(os.EOL).filter(name => name !== '');
 };
 
-const launchEmulator = emulatorName => {
+const launchEmulator = (emulatorName /*: string */) => {
   // we need both options 'cause reasons:
   // from docs: "When using the detached option to start a long-running process, the process will not stay running in the background after the parent exits unless it is provided with a stdio configuration that is not connected to the parent. If the parent's stdio is inherited, the child will remain attached to the controlling terminal."
   // here: https://nodejs.org/api/child_process.html#optionsdetached
 
-  const child_process = spawn(emulatorCommand, [`@${emulatorName}`], {
-    detached: true,
-    stdio: 'ignore',
-  });
+  const child_process /*: child_process$ChildProcess */ = spawn(
+    emulatorCommand,
+    [`@${emulatorName}`],
+    {
+      detached: true,
+      stdio: 'ignore',
+    },
+  );
 
   child_process.unref();
 };
@@ -107,8 +118,8 @@ function maybeLaunchAndroidEmulator() {
 // inspired by CLI again https://github.com/react-native-community/cli/blob/main/packages/cli-tools/src/isPackagerRunning.ts
 
 function isPackagerRunning(
-  packagerPort = process.env.RCT_METRO_PORT || '8081',
-) {
+  packagerPort /*: string */ = process.env.RCT_METRO_PORT ?? '8081',
+) /*: 'running' | 'unrecognized' | 'not_running' */ {
   try {
     const status = exec(`curl http://localhost:${packagerPort}/status`, {
       silent: true,
@@ -121,7 +132,7 @@ function isPackagerRunning(
 }
 
 // this is a very limited implementation of how this should work
-function launchPackagerInSeparateWindow(folderPath) {
+function launchPackagerInSeparateWindow(folderPath /*: string */) {
   const command = `tell application "Terminal" to do script "cd ${folderPath} && yarn start"`;
   exec(`osascript -e '${command}' >/dev/null <<EOF`);
 }
@@ -146,8 +157,11 @@ function checkPackagerRunning() {
  * - @circleciToken a valid CircleCI Token.
  * - @branchName the branch of the name we want to use to fetch the artifacts.
  */
-async function setupCircleCIArtifacts(circleciToken, branchName) {
-  if (!circleciToken) {
+async function setupCircleCIArtifacts(
+  circleciToken /*: ?string */,
+  branchName /*: string */,
+) /*: Promise<?typeof circleCIArtifactsUtils> */ {
+  if (circleciToken == null) {
     return null;
   }
 
@@ -161,9 +175,9 @@ async function setupCircleCIArtifacts(circleciToken, branchName) {
 }
 
 async function downloadArtifactsFromCircleCI(
-  circleCIArtifacts,
-  mavenLocalPath,
-  localNodeTGZPath,
+  circleCIArtifacts /*: typeof circleCIArtifactsUtils */,
+  mavenLocalPath /*: string */,
+  localNodeTGZPath /*: string */,
 ) {
   const mavenLocalURL = await circleCIArtifacts.artifactURLForMavenLocal();
   const hermesURL = await circleCIArtifacts.artifactURLHermesDebug();
@@ -187,9 +201,9 @@ async function downloadArtifactsFromCircleCI(
 }
 
 function buildArtifactsLocally(
-  releaseVersion,
-  buildType,
-  reactNativePackagePath,
+  releaseVersion /*: string */,
+  buildType /*: BuildType */,
+  reactNativePackagePath /*: string */,
 ) {
   // this is needed to generate the Android artifacts correctly
   const exitCode = exec(
@@ -264,13 +278,13 @@ function buildArtifactsLocally(
  * - @hermesPath the path to hermes for iOS
  */
 async function prepareArtifacts(
-  circleCIArtifacts,
-  mavenLocalPath,
-  localNodeTGZPath,
-  releaseVersion,
-  buildType,
-  reactNativePackagePath,
-) {
+  circleCIArtifacts /*: ?typeof circleCIArtifactsUtils */,
+  mavenLocalPath /*: string */,
+  localNodeTGZPath /*: string */,
+  releaseVersion /*: string */,
+  buildType /*: BuildType */,
+  reactNativePackagePath /*: string */,
+) /*: Promise<string> */ {
   return circleCIArtifacts != null
     ? await downloadArtifactsFromCircleCI(
         circleCIArtifacts,
diff --git a/scripts/update-template-package.js b/scripts/update-template-package.js
index b3203f4c7dd299..be6abec363c3e5 100755
--- a/scripts/update-template-package.js
+++ b/scripts/update-template-package.js
@@ -4,6 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
+ * @flow strict-local
  * @format
  */
 
@@ -20,11 +21,12 @@ const path = require('path');
  * `dependencyMap` is a dict of package name to its version
  * ex. {"react-native": "0.23.0", "other-dep": "nightly"}
  */
-function updateTemplatePackage(dependencyMap) {
+function updateTemplatePackage(dependencyMap /*: {[string]: string} */) {
   const jsonPath = path.join(
     __dirname,
     '../packages/react-native/template/package.json',
   );
+  // $FlowIgnore[unsupported-syntax]
   const templatePackageJson = require(jsonPath);
 
   const updatedPackageJson = applyPackageVersions(