diff --git a/_includes/head.html b/_includes/head.html
index 24e38d43..a1e12fc6 100644
--- a/_includes/head.html
+++ b/_includes/head.html
@@ -6,7 +6,7 @@
   <link rel="stylesheet" href="{{ site.url }}/assets/css/main.css" />
   <link rel="shortcut icon" type="image/x-icon" href="/{{ site.favicon }}" />
   <link rel="stylesheet" href="{{ site.url }}/assets/css/agate.css" />
-  <script src="http://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.4.0/highlight.min.js"></script>
+  <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.4.0/highlight.min.js"></script>
   <script>
     hljs.initHighlightingOnLoad();
   </script>