diff --git a/_includes/themes/flat/default.html b/_includes/themes/flat/default.html
index 00d88c79c..f532734e0 100644
--- a/_includes/themes/flat/default.html
+++ b/_includes/themes/flat/default.html
@@ -23,6 +23,13 @@
     {% assign page_tags = page.tags | join: ', ' %}
     {% assign page_keywords = page_tags | append: ', ' | append: page_keywords %}
     {% endif %}
+    <!-- Google Tag Manager -->
+    <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
+        new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
+      j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
+      'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
+    })(window,document,'script','dataLayer','GTM-MN8W29W4');</script>
+    <!-- End Google Tag Manager -->
 
     <meta name="keywords" content="{{ page_keywords }}">
     
@@ -102,6 +109,10 @@
 </head>
 
 <body>
+<!-- Google Tag Manager (noscript) -->
+<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-MN8W29W4"
+                  height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
+<!-- End Google Tag Manager (noscript) -->
 
    <nav class="navbar navbar-light navbar-expand-lg">
       <div class="container navContainer">
