diff --git a/app/sanitizers/rendered_markdown_scrubber.rb b/app/sanitizers/rendered_markdown_scrubber.rb
index e6136841d6024..72d217d34f966 100644
--- a/app/sanitizers/rendered_markdown_scrubber.rb
+++ b/app/sanitizers/rendered_markdown_scrubber.rb
@@ -1,7 +1,7 @@
 class RenderedMarkdownScrubber < Rails::Html::PermitScrubber
   def initialize
     super
-    self.tags = %w[a abbr add aside b blockquote br button center cite code col colgroup dd del dl dt em em figcaption h1 h2 h3 h4 h5 h6 hr i img kbd li ol p pre q rp rt ruby small source span strong sub sup table tbody td tfoot th thead time tr u ul video]
+    self.tags = %w[a abbr add aside b blockquote br button center cite code col colgroup dd del dl dt em em figcaption h1 h2 h3 h4 h5 h6 hr i img kbd li mark ol p pre q rp rt ruby small source span strong sub sup table tbody td tfoot th thead time tr u ul video]
     self.attributes = %w[alt class colspan data-conversation data-lang data-no-instant data-url em height href id loop name ref rel rowspan size span src start strong title type value width]
   end