diff --git a/src/markup/syntax/highlighter/PhutilPygmentsSyntaxHighlighter.php b/src/markup/syntax/highlighter/PhutilPygmentsSyntaxHighlighter.php
--- a/src/markup/syntax/highlighter/PhutilPygmentsSyntaxHighlighter.php
+++ b/src/markup/syntax/highlighter/PhutilPygmentsSyntaxHighlighter.php
@@ -173,6 +173,7 @@
       'rl' => 'ragel-em',
       'robot' => 'robotframework',
       'Rout' => 'rconsole',
+      'rs' => 'rust',
       'rss' => 'xml',
       's' => 'gas',
       'S' => 'splus',