diff --git a/gulpfile.js b/gulpfile.js
index 65f285c5a..56cc2f55e 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -16,8 +16,10 @@ var buildTasks = require('./scripts/gulpfiles/build_tasks');
 var packageTasks = require('./scripts/gulpfiles/package_tasks');
 var gitTasks = require('./scripts/gulpfiles/git_tasks');
 var licenseTasks = require('./scripts/gulpfiles/license_tasks');
+var appengineTasks = require('./scripts/gulpfiles/appengine_tasks');
 
 module.exports = {
+  deployDemos: appengineTasks.deployDemos,
   default: buildTasks.build,
   build: buildTasks.build,
   buildCore: buildTasks.core,
diff --git a/package.json b/package.json
index ea8351d6e..a0e6acc7c 100644
--- a/package.json
+++ b/package.json
@@ -29,6 +29,7 @@
     "build:langfiles": "gulp buildLangfiles",
     "build:uncompressed": "gulp buildUncompressed",
     "bump": "npm --no-git-tag-version version 4.$(date +'%Y%m%d').0",
+    "deployDemos": "gulp deployDemos",
     "license": "gulp checkLicenses",
     "lint": "eslint .",
     "package": "gulp package",
diff --git a/scripts/gulpfiles/appengine_tasks.js b/scripts/gulpfiles/appengine_tasks.js
new file mode 100644
index 000000000..cc22d151c
--- /dev/null
+++ b/scripts/gulpfiles/appengine_tasks.js
@@ -0,0 +1,85 @@
+/**
+ * @license
+ * Copyright 2020 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Gulp script to deploy Blockly demos on appengine.
+ */
+
+var gulp = require('gulp');
+
+var fs = require('fs');
+var rimraf = require('rimraf');
+var execSync = require('child_process').execSync;
+
+var packageJson = require('../../package.json');
+
+const demoTmpDir = '../_deploy';
+const demoStaticTmpDir = '../_deploy/static';
+
+/**
+ * Cleans and creates the tmp directory used for deploying.
+ */
+function prepareDeployDir(done) {
+  // Clean directory if exists.
+  if (fs.existsSync(demoTmpDir)) {
+    rimraf.sync(demoTmpDir);
+  }
+  fs.mkdirSync(demoStaticTmpDir, { recursive: true });
+  done()
+}
+
+/**
+ * Copies all files into static deploy directory except for those under
+ * appengine.
+ */
+function copyStaticSrc(done) {
+  execSync(`git archive HEAD | tar -x -C ${demoStaticTmpDir}`,
+      { stdio: 'inherit' });
+  done()
+}
+
+/**
+ * Copies appengine files into deploy directory.
+ */
+function copyAppengineSrc() {
+  return gulp.src(['appengine/**/*', 'appengine/.gcloudignore',])
+      .pipe(gulp.dest(demoTmpDir));
+}
+
+/**
+ * Deploys files from tmp directory to appengine to the minor version defined in
+ * package.json and then cleans the tmp directory.
+ */
+function deployAndClean(done) {
+  const minorVersion = packageJson.version.split('.')[1];
+  const patchVersion = packageJson.version.split('.')[2];
+  let demoVersion = minorVersion;
+  if (patchVersion != 0) {
+    demoVersion += '-' + patchVersion
+  }
+  try {
+    execSync(`gcloud app deploy --project blockly-demo --version ${demoVersion} --no-promote`, { stdio: 'inherit', cwd: demoTmpDir });
+  } finally {
+    // Clean up tmp directory.
+    if (fs.existsSync(demoTmpDir)) {
+      rimraf.sync(demoTmpDir);
+    }
+  }
+  done();
+}
+
+/**
+ * Deploys demos.
+ */
+const deployDemos = gulp.series(
+    prepareDeployDir,
+    gulp.parallel(copyStaticSrc, copyAppengineSrc),
+    deployAndClean
+);
+
+module.exports = {
+  deployDemos: deployDemos,
+}