diff --git a/core/templates/external-js/tiddlywiki5-external-js.html.tid b/core/templates/external-js/tiddlywiki5-external-js.html.tid
index f4747e308..31e583c6c 100644
--- a/core/templates/external-js/tiddlywiki5-external-js.html.tid
+++ b/core/templates/external-js/tiddlywiki5-external-js.html.tid
@@ -2,7 +2,7 @@ title: $:/core/templates/tiddlywiki5-external-js.html
 
 \rules only filteredtranscludeinline transcludeinline
 <!doctype html>
-{{$:/core/templates/MOTW.html}}<html>
+{{$:/core/templates/MOTW.html}}<html lang="`<$text text={{{ [{$:/language}get[name]] }}}/>`">
 <head>
 <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
 <!--~~ Raw markup for the top of the head section ~~-->
diff --git a/core/templates/tiddlywiki5.html.tid b/core/templates/tiddlywiki5.html.tid
index 377e4fef5..ef5a7e1ea 100644
--- a/core/templates/tiddlywiki5.html.tid
+++ b/core/templates/tiddlywiki5.html.tid
@@ -2,7 +2,7 @@ title: $:/core/templates/tiddlywiki5.html
 
 <$set name="saveTiddlerAndShadowsFilter" filter="[subfilter<saveTiddlerFilter>] [subfilter<saveTiddlerFilter>plugintiddlers[]]">
 `<!doctype html>
-`{{$:/core/templates/MOTW.html}}`<html>
+`{{$:/core/templates/MOTW.html}}`<html lang="`<$text text={{{ [{$:/language}get[name]] }}}/>`">
 <head>
 <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
 <!--~~ Raw markup for the top of the head section ~~-->
