diff --git a/vendor/fbtransform/transforms/xjs.js b/vendor/fbtransform/transforms/xjs.js
index 9811c45d23..acac965f87 100644
--- a/vendor/fbtransform/transforms/xjs.js
+++ b/vendor/fbtransform/transforms/xjs.js
@@ -143,6 +143,7 @@ var knownTags = {
   title: true,
   tr: true,
   track: true,
+  tspan: true,
   u: true,
   ul: true,
   'var': true,