diff --git a/src/SqlFormatter.php b/src/SqlFormatter.php
index 4fe4c46..009cdc3 100644
--- a/src/SqlFormatter.php
+++ b/src/SqlFormatter.php
@@ -47,7 +47,7 @@ public function __construct(?Highlighter $highlighter = null)
      *
      * @return string The SQL string with HTML styles and formatting wrapped in a <pre> tag
      */
-    public function format(string $string, string $indentString = '  '): string
+    public function format(string $string, string $indentString = '  ', bool $forceUppercase = false): string
     {
         // This variable will be populated with formatted html
         $return = '';
@@ -71,9 +71,23 @@ public function format(string $string, string $indentString = '  '): string
 
         // Format token by token
         while ($token = $cursor->next(Token::TOKEN_TYPE_WHITESPACE)) {
+            // Uppercase reserved words
+            $uppercaseTypes = [
+                Token::TOKEN_TYPE_RESERVED,
+                Token::TOKEN_TYPE_RESERVED_NEWLINE,
+                Token::TOKEN_TYPE_RESERVED_TOPLEVEL
+            ];
+
+            // Uppercase transformation if desired
+            if ($forceUppercase && in_array($token->type(), $uppercaseTypes)) {                
+                $tokenValue = strtoupper($token->value());
+            } else {
+                $tokenValue = $token->value();
+            }
+
             $highlighted = $this->highlighter->highlightToken(
                 $token->type(),
-                $token->value()
+                $tokenValue
             );
 
             // If we are increasing the special indent level now
diff --git a/tests/SqlFormatterTest.php b/tests/SqlFormatterTest.php
index 68d90cd..4edb9d9 100644
--- a/tests/SqlFormatterTest.php
+++ b/tests/SqlFormatterTest.php
@@ -60,6 +60,16 @@ public function testFormat(string $sql, string $html): void
         $this->assertEquals(trim($html), trim($formatter->format($sql)));
     }
 
+    public function testFormatUpperCase(): void
+    {
+        $formatter = new SqlFormatter(new NullHighlighter());
+
+        $actual = $formatter->format('select a from b where c = d;', ' ', true);
+        $expected = "SELECT\n a\nFROM\n b\nWHERE\n c = d;";
+
+        $this->assertEquals(trim($expected), trim($actual));
+    }
+
     /**
      * @dataProvider highlightData
      */