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
@@ -295,6 +295,8 @@
     'PhutilProtocolChannel' => 'channel/PhutilProtocolChannel.php',
     'PhutilProxyException' => 'error/PhutilProxyException.php',
     'PhutilProxyIterator' => 'utils/PhutilProxyIterator.php',
+    'PhutilPygmentizeParser' => 'parser/PhutilPygmentizeParser.php',
+    'PhutilPygmentizeParserTestCase' => 'parser/__tests__/PhutilPygmentizeParserTestCase.php',
     'PhutilPygmentsSyntaxHighlighter' => 'markup/syntax/highlighter/PhutilPygmentsSyntaxHighlighter.php',
     'PhutilPythonFragmentLexer' => 'lexer/PhutilPythonFragmentLexer.php',
     'PhutilQsprintfInterface' => 'xsprintf/PhutilQsprintfInterface.php',
@@ -850,6 +852,8 @@
       'Phobject',
       'Iterator',
     ),
+    'PhutilPygmentizeParser' => 'Phobject',
+    'PhutilPygmentizeParserTestCase' => 'PhutilTestCase',
     'PhutilPygmentsSyntaxHighlighter' => 'Phobject',
     'PhutilPythonFragmentLexer' => 'PhutilLexer',
     'PhutilQueryStringParser' => 'Phobject',
diff --git a/src/parser/PhutilPygmentizeParser.php b/src/parser/PhutilPygmentizeParser.php
new file mode 100644
--- /dev/null
+++ b/src/parser/PhutilPygmentizeParser.php
@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * Parser that converts `pygmetize` output or similar HTML blocks from "class"
+ * attributes to "style" attributes.
+ */
+final class PhutilPygmentizeParser extends Phobject {
+
+  private $map = array();
+
+  public function setMap(array $map) {
+    $this->map = $map;
+    return $this;
+  }
+
+  public function getMap() {
+    return $this->map;
+  }
+
+  public function parse($block) {
+    $class_look = 'class="';
+    $class_len = strlen($class_look);
+
+    $class_start = null;
+
+    $map = $this->map;
+
+    $len = strlen($block);
+    $out = '';
+    $mode = 'text';
+    for ($ii = 0; $ii < $len; $ii++) {
+      $c = $block[$ii];
+      switch ($mode) {
+        case 'text':
+          // We're in general text between tags, and just passing characers
+          // through unmodified.
+          if ($c == '<') {
+            $mode = 'tag';
+          }
+          $out .= $c;
+          break;
+        case 'tag':
+          // We're inside a tag, and looking for `class="` so we can rewrite
+          // it.
+          if ($c == '>') {
+            $mode = 'text';
+          }
+          if ($c == 'c') {
+            if (!substr_compare($block, $class_look, $ii, $class_len)) {
+              $mode = 'class';
+              $ii += $class_len;
+              $class_start = $ii;
+            }
+          }
+
+          if ($mode != 'class') {
+            $out .= $c;
+          }
+          break;
+        case 'class':
+          // We're inside a `class="..."` tag, and looking for the ending quote
+          // so we can replace it.
+          if ($c == '"') {
+            $class = substr($block, $class_start, $ii - $class_start);
+
+            // If this class is present in the map, rewrite it into an inline
+            // style attribute.
+            if (isset($map[$class])) {
+              $out .= 'style="'.phutil_escape_html($map[$class]).'"';
+            } else {
+              $out .= 'class="'.$class.'"';
+            }
+
+            $mode = 'tag';
+          }
+          break;
+      }
+    }
+
+    return $out;
+  }
+
+}
diff --git a/src/parser/__tests__/PhutilPygmentizeParserTestCase.php b/src/parser/__tests__/PhutilPygmentizeParserTestCase.php
new file mode 100644
--- /dev/null
+++ b/src/parser/__tests__/PhutilPygmentizeParserTestCase.php
@@ -0,0 +1,43 @@
+<?php
+
+final class PhutilPygmentizeParserTestCase extends PhutilTestCase {
+
+  public function testPygmentizeParser() {
+    $this->tryParser(
+      '',
+      '',
+      array(),
+      pht('Empty'));
+
+    $this->tryParser(
+      '<span class="mi">1</span>',
+      '<span style="color: #ff0000">1</span>',
+      array(
+        'mi' => 'color: #ff0000',
+      ),
+      pht('Simple'));
+
+    $this->tryParser(
+      '<span class="mi">1</span>',
+      '<span class="mi">1</span>',
+      array(),
+      pht('Missing Class'));
+
+    $this->tryParser(
+      '<span data-symbol-name="X" class="nc">X</span>',
+      '<span data-symbol-name="X" style="color: #ff0000">X</span>',
+      array(
+        'nc' => 'color: #ff0000',
+      ),
+      pht('Extra Attribute'));
+  }
+
+  private function tryParser($input, $expect, array $map, $label) {
+    $actual = id(new PhutilPygmentizeParser())
+      ->setMap($map)
+      ->parse($input);
+
+    $this->assertEqual($expect, $actual, pht('Pygmentize Parser: %s', $label));
+  }
+
+}