diff --git a/tools/check b/tools/check
index 5ab68670ed1fa8e786c7c84cc5b37caa65e134ea..c7dbf9d3a76f49802d254e01ba33932a633ec71c 100755
--- a/tools/check
+++ b/tools/check
@@ -406,7 +406,8 @@ class TopicPageValidator(MarkdownValidator):
 class MotivationPageValidator(MarkdownValidator):
     """Validate motivation.md"""
     DOC_HEADERS = {"layout": vh.is_str,
-                   "title": vh.is_str}
+                   "title": vh.is_str,
+                   "subtitle": vh.is_str}
     # TODO: How to validate? May be a mix of reveal.js (HTML) + markdown.