diff --git a/src/markup/engine/__tests__/remarkup/header-skip.txt b/src/markup/engine/__tests__/remarkup/header-skip.txt
new file mode 100644
--- /dev/null
+++ b/src/markup/engine/__tests__/remarkup/header-skip.txt
@@ -0,0 +1,11 @@
+#2 is my favorite.
+
+#project
+~~~~~~~~~~
+<p>#2 is my favorite.</p>
+
+<p>#project</p>
+~~~~~~~~~~
+#2 is my favorite.
+
+#project
diff --git a/src/markup/engine/remarkup/blockrule/PhutilRemarkupHeaderBlockRule.php b/src/markup/engine/remarkup/blockrule/PhutilRemarkupHeaderBlockRule.php
--- a/src/markup/engine/remarkup/blockrule/PhutilRemarkupHeaderBlockRule.php
+++ b/src/markup/engine/remarkup/blockrule/PhutilRemarkupHeaderBlockRule.php
@@ -4,7 +4,7 @@
 
   public function getMatchingLineCount(array $lines, $cursor) {
     $num_lines = 0;
-    if (preg_match('/^([=|#]{1,5}).*+$/', $lines[$cursor])) {
+    if (preg_match('/^(={1,5}|#{2,5}|# ).*+$/', $lines[$cursor])) {
       $num_lines = 1;
     } else {
       if (isset($lines[$cursor + 1])) {