diff --git a/docs/config/02-files.md b/docs/config/02-files.md
index d7d267484..fde05c962 100644
--- a/docs/config/02-files.md
+++ b/docs/config/02-files.md
@@ -52,6 +52,11 @@ Each pattern is either a simple string or an object with four properties:
 * **Default.** `true`
 * **Description.** Should the files be served by Karma's webserver?
 
+### `esModule`
+* **Type.** Boolean
+* **Default.** `false`
+* **Description.** Should the files be loaded as ECMAScript modules?
+
 ### `nocache`
 * **Type.** Boolean
 * **Default.** `false`
diff --git a/lib/config.js b/lib/config.js
index deeaf6d7d..540b309eb 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -30,11 +30,12 @@ try {
   TYPE_SCRIPT_AVAILABLE = true
 } catch (e) {}
 
-var Pattern = function (pattern, served, included, watched, nocache) {
+var Pattern = function (pattern, served, included, watched, nocache, esModule) {
   this.pattern = pattern
   this.served = helper.isDefined(served) ? served : true
   this.included = helper.isDefined(included) ? included : true
   this.watched = helper.isDefined(watched) ? watched : true
+  this.esModule = helper.isDefined(esModule) ? esModule : false
   this.nocache = helper.isDefined(nocache) ? nocache : false
   this.weight = helper.mmPatternWeight(pattern)
 }
@@ -44,7 +45,7 @@ Pattern.prototype.compare = function (other) {
 }
 
 var UrlPattern = function (url) {
-  Pattern.call(this, url, false, true, false, false)
+  Pattern.call(this, url, false, true, false, false, false)
 }
 
 var createPatternObject = function (pattern) {
@@ -61,7 +62,8 @@ var createPatternObject = function (pattern) {
           pattern.served,
           pattern.included,
           pattern.watched,
-          pattern.nocache)
+          pattern.nocache,
+          pattern.esModule)
     }
 
     log.warn('Invalid pattern %s!\n\tObject is missing "pattern" property.', pattern)
diff --git a/lib/file-list.js b/lib/file-list.js
index ca9c9e2e2..0e2024461 100644
--- a/lib/file-list.js
+++ b/lib/file-list.js
@@ -183,7 +183,8 @@ List.prototype._refresh = function () {
 
       var mtime = mg.statCache[path].mtime
       var doNotCache = patternObject.nocache
-      var file = new File(path, mtime, doNotCache)
+      var esModule = patternObject.esModule
+      var file = new File(path, mtime, doNotCache, esModule)
 
       if (file.doNotCache) {
         log.debug('Not preprocessing "%s" due to nocache')
diff --git a/lib/file.js b/lib/file.js
index 4eabe8e00..2c261eddb 100644
--- a/lib/file.js
+++ b/lib/file.js
@@ -9,7 +9,7 @@
 var _ = require('lodash')
 
 // Constructor
-var File = function (path, mtime, doNotCache) {
+var File = function (path, mtime, doNotCache, esModule) {
   // used for serving (processed path, eg some/file.coffee -> some/file.coffee.js)
   this.path = path
 
@@ -23,6 +23,7 @@ var File = function (path, mtime, doNotCache) {
   this.isUrl = false
 
   this.doNotCache = _.isUndefined(doNotCache) ? false : doNotCache
+  this.esModule = esModule
 }
 
 File.prototype.toString = function () {
diff --git a/lib/middleware/karma.js b/lib/middleware/karma.js
index 04dd47a3f..ed0d31c59 100644
--- a/lib/middleware/karma.js
+++ b/lib/middleware/karma.js
@@ -178,6 +178,7 @@ var createKarmaMiddleware = function (
             var file = files.included[i]
             var filePath = file.path
             var fileExt = path.extname(filePath)
+            var esModule = fileExt.endsWith('js') && file.esModule
 
             if (!files.included.hasOwnProperty(i)) {
               continue
@@ -204,7 +205,7 @@ var createKarmaMiddleware = function (
             }
 
             // The script tag to be placed
-            var scriptType = (SCRIPT_TYPE[fileExt] || 'text/javascript')
+            var scriptType = esModule ? 'module' : (SCRIPT_TYPE[fileExt] || 'text/javascript')
 
             // In case there is a JavaScript version specified and this is a Firefox browser
             if (jsVersion && jsVersion > 0 && isFirefox(request)) {