diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -296,6 +296,7 @@
     'PhutilRemarkupEngineTestCase' => 'markup/engine/__tests__/PhutilRemarkupEngineTestCase.php',
     'PhutilRemarkupEscapeRemarkupRule' => 'markup/engine/remarkup/markuprule/PhutilRemarkupEscapeRemarkupRule.php',
     'PhutilRemarkupHeaderBlockRule' => 'markup/engine/remarkup/blockrule/PhutilRemarkupHeaderBlockRule.php',
+    'PhutilRemarkupHighlightRule' => 'markup/engine/remarkup/markuprule/PhutilRemarkupHighlightRule.php',
     'PhutilRemarkupHorizontalRuleBlockRule' => 'markup/engine/remarkup/blockrule/PhutilRemarkupHorizontalRuleBlockRule.php',
     'PhutilRemarkupHyperlinkRule' => 'markup/engine/remarkup/markuprule/PhutilRemarkupHyperlinkRule.php',
     'PhutilRemarkupInlineBlockRule' => 'markup/engine/remarkup/blockrule/PhutilRemarkupInlineBlockRule.php',
@@ -817,6 +818,7 @@
     'PhutilRemarkupEngineTestCase' => 'PhutilTestCase',
     'PhutilRemarkupEscapeRemarkupRule' => 'PhutilRemarkupRule',
     'PhutilRemarkupHeaderBlockRule' => 'PhutilRemarkupBlockRule',
+    'PhutilRemarkupHighlightRule' => 'PhutilRemarkupRule',
     'PhutilRemarkupHorizontalRuleBlockRule' => 'PhutilRemarkupBlockRule',
     'PhutilRemarkupHyperlinkRule' => 'PhutilRemarkupRule',
     'PhutilRemarkupInlineBlockRule' => 'PhutilRemarkupBlockRule',
diff --git a/src/markup/engine/__tests__/PhutilRemarkupEngineTestCase.php b/src/markup/engine/__tests__/PhutilRemarkupEngineTestCase.php
--- a/src/markup/engine/__tests__/PhutilRemarkupEngineTestCase.php
+++ b/src/markup/engine/__tests__/PhutilRemarkupEngineTestCase.php
@@ -85,6 +85,7 @@
     $rules[] = new PhutilRemarkupItalicRule();
     $rules[] = new PhutilRemarkupDelRule();
     $rules[] = new PhutilRemarkupUnderlineRule();
+    $rules[] = new PhutilRemarkupHighlightRule();
 
     $blocks = array();
     $blocks[] = new PhutilRemarkupQuotesBlockRule();
diff --git a/src/markup/engine/__tests__/remarkup/highlight.txt b/src/markup/engine/__tests__/remarkup/highlight.txt
new file mode 100644
--- /dev/null
+++ b/src/markup/engine/__tests__/remarkup/highlight.txt
@@ -0,0 +1,7 @@
+how about we !!highlight!! some !!TEXT!!!
+wow this must be **!!very important!!**
+~~~~~~~~~~
+<p>how about we <span class="remarkup-highlight">highlight</span> some <span class="remarkup-highlight">TEXT!</span>
+wow this must be <strong><span class="remarkup-highlight">very important</span></strong></p>
+~~~~~~~~~~
+how about we !!highlight!! some !!TEXT!!! wow this must be **!!very important!!**
diff --git a/src/markup/engine/remarkup/markuprule/PhutilRemarkupHighlightRule.php b/src/markup/engine/remarkup/markuprule/PhutilRemarkupHighlightRule.php
new file mode 100644
--- /dev/null
+++ b/src/markup/engine/remarkup/markuprule/PhutilRemarkupHighlightRule.php
@@ -0,0 +1,30 @@
+<?php
+
+final class PhutilRemarkupHighlightRule extends PhutilRemarkupRule {
+
+  public function getPriority() {
+    return 1000.0;
+  }
+
+  public function apply($text) {
+    if ($this->getEngine()->isTextMode()) {
+      return $text;
+    }
+
+    return $this->replaceHTML(
+      '@!!(.+?)(!{2,})@',
+      array($this, 'applyCallback'),
+      $text);
+  }
+
+  protected function applyCallback(array $matches) {
+    // Remove the two exclamation points that represent syntax.
+    $excitement = substr($matches[2], 2);
+
+    // $excitement now has two fewer !'s than we started with.
+    return hsprintf('<span class="remarkup-highlight">%s%s</span>',
+      $matches[1], $excitement);
+
+  }
+
+}