diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 1bed4ecd..524f81bf 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1031,6 +1031,7 @@ HTML:
   - .htm
   - .st
   - .xhtml
+  - .xht
 
 HTML+Django:
   type: markup
diff --git a/samples/HTML/example.xht b/samples/HTML/example.xht
new file mode 100644
index 00000000..a49a0a53
--- /dev/null
+++ b/samples/HTML/example.xht
@@ -0,0 +1,17 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
+    <head>
+        <title>This is a XHTML sample file</title>
+        <style type="text/css"><![CDATA[
+            #example {
+                background-color: yellow;
+            }
+        ]]></style>
+    </head>
+    <body>
+        <div id="example">
+            Just a simple <strong>XHTML</strong> test page.
+        </div>
+    </body>
+</html>
+
