diff --git a/src/components/subtitleuploader/subtitleuploader.js b/src/components/subtitleuploader/subtitleuploader.js
index 6cd3f1ff2..e5e262c2e 100644
--- a/src/components/subtitleuploader/subtitleuploader.js
+++ b/src/components/subtitleuploader/subtitleuploader.js
@@ -32,7 +32,7 @@ function onFileReaderError(evt) {
 }
 
 function isValidSubtitleFile(file) {
-    return file && ['.sub', '.srt', '.vtt', '.ass', '.ssa']
+    return file && ['.sub', '.srt', '.vtt', '.ass', '.ssa', '.mks']
         .some(function(ext) {
             return file.name.endsWith(ext);
         });
diff --git a/src/components/subtitleuploader/subtitleuploader.template.html b/src/components/subtitleuploader/subtitleuploader.template.html
index 7febd1e7a..7a498c061 100644
--- a/src/components/subtitleuploader/subtitleuploader.template.html
+++ b/src/components/subtitleuploader/subtitleuploader.template.html
@@ -22,7 +22,7 @@
                 <div class="subtitleEditor-dropZone fieldDescription">
                     <div id="labelDropSubtitle">${LabelDropSubtitleHere}</div>
                     <output id="subtitleOutput" class="flex align-items-center justify-content-center" style="position: absolute;top:0;left:0;right:0;bottom:0;width:100%;"></output>
-                    <input type="file" accept=".sub,.srt,.vtt,.ass,.ssa" id="uploadSubtitle" name="uploadSubtitle" style="position: absolute;top:0;left:0;right:0;bottom:0;width:100%;opacity:0;"/>
+                    <input type="file" accept=".sub,.srt,.vtt,.ass,.ssa,.mks" id="uploadSubtitle" name="uploadSubtitle" style="position: absolute;top:0;left:0;right:0;bottom:0;width:100%;opacity:0;"/>
                 </div>
                 <div id="fldUpload" class="hide">
                     <br />