diff --git a/phpBB/phpbb/template/twig/lexer.php b/phpBB/phpbb/template/twig/lexer.php
index bd9ece57fd..d47162951d 100644
--- a/phpBB/phpbb/template/twig/lexer.php
+++ b/phpBB/phpbb/template/twig/lexer.php
@@ -229,18 +229,18 @@ class phpbb_template_twig_lexer extends Twig_Lexer
 		{
 			$inner = $matches[2];
 			// Replace $TEST with definition.TEST
-			$inner = preg_replace('#\s\$([a-zA-Z_0-9]+)#', ' definition.$1', $inner);
+			$inner = preg_replace('#(\s\(?!?)\$([a-zA-Z_0-9]+)#', '$1definition.$2', $inner);
 
 			// Replace .foo with loops.foo|length
-			$inner = preg_replace('#\s\.([a-zA-Z_0-9]+)([^a-zA-Z_0-9\.])#', ' loops.$1|length$2', $inner);
+			$inner = preg_replace('#(\s\(?!?)\.([a-zA-Z_0-9]+)([^a-zA-Z_0-9\.])#', '$1loops.$2|length$3', $inner);
 
 			// Replace .foo.bar with foo.bar|length
-			$inner = preg_replace('#\s\.([a-zA-Z_0-9\.]+)([^a-zA-Z_0-9\.])#', ' $1|length$2', $inner);
+			$inner = preg_replace('#(\s\(?!?)\.([a-zA-Z_0-9\.]+)([^a-zA-Z_0-9\.])#', '$1$2|length$3', $inner);
 
 			return "<!-- {$matches[1]}IF{$inner}-->";
 		};
 
-		return preg_replace_callback('#<!-- (ELSE)?IF((.*?)[\s][\$|\.|!]([^\s]+)(.*?))-->#', $callback, $code);
+		return preg_replace_callback('#<!-- (ELSE)?IF((.*?) \(?!?[\$|\.]([^\s]+)(.*?))-->#', $callback, $code);
 	}
 
 	/**
diff --git a/tests/template/template_test.php b/tests/template/template_test.php
index e64493e59a..1649604492 100644
--- a/tests/template/template_test.php
+++ b/tests/template/template_test.php
@@ -158,7 +158,7 @@ class phpbb_template_template_test extends phpbb_template_template_test_case
 				array(),
 				array('test_loop' => array(array(), array(), array(), array(), array(), array(), array()), 'test' => array(array()), 'test.deep' => array(array()), 'test.deep.defines' => array(array())),
 				array(),
-				"xyz\nabc\n\$VALUE == 'abc'abc\nbar\nbar\nabc\ntest!@#$%^&*()_-=+{}[]:;\",<.>/?\n[]|foobar|",
+				"xyz\nabc\n\$VALUE == 'abc'\n(\$VALUE == 'abc')\n!\$DOESNT_EXIST\n(!\$DOESNT_EXIST)\nabc\nbar\nbar\nabc\ntest!@#$%^&*()_-=+{}[]:;\",<.>/?[]|foobar|",
 			),
 			array(
 				'define_advanced.html',
diff --git a/tests/template/templates/define.html b/tests/template/templates/define.html
index f519078a5b..bc20c02ed1 100644
--- a/tests/template/templates/define.html
+++ b/tests/template/templates/define.html
@@ -7,6 +7,15 @@ $VALUE != 'abc'
 <!-- ELSEIF $VALUE == 'abc' -->
 $VALUE == 'abc'
 <!-- ENDIF -->
+<!-- IF ($VALUE == 'abc') -->
+($VALUE == 'abc')
+<!-- ENDIF -->
+<!-- IF !$DOESNT_EXIST -->
+!$DOESNT_EXIST
+<!-- ENDIF -->
+<!-- IF (!$DOESNT_EXIST) -->
+(!$DOESNT_EXIST)
+<!-- ENDIF -->
 <!-- INCLUDE define_include.html -->
 {$INCLUDED_VALUE}
 {$VALUE}