diff --git a/assets/less/components/_media.less b/assets/less/components/_media.less
index 78458a2..349fe12 100644
--- a/assets/less/components/_media.less
+++ b/assets/less/components/_media.less
@@ -3,6 +3,10 @@
   &:extend(.thumbnail all);
 }
 
+.wp-caption-text {
+    &:extend(.thumbnail .caption);
+}
+
 // Gallery shortcode
 .gallery-row {
   padding: (@line-height-computed / 2) 0;
diff --git a/lib/init.php b/lib/init.php
index 686673e..d70a899 100644
--- a/lib/init.php
+++ b/lib/init.php
@@ -23,6 +23,10 @@ function roots_setup() {
   // http://codex.wordpress.org/Post_Formats
   add_theme_support('post-formats', array('aside', 'gallery', 'link', 'image', 'quote', 'video', 'audio'));
 
+  // Add HTML5 markup for captions
+  // http://codex.wordpress.org/Function_Reference/add_theme_support#HTML5
+  add_theme_support('html5', array('caption'));
+
   // Tell the TinyMCE editor to use a custom stylesheet
   add_editor_style('/assets/css/editor-style.css');
 }