diff --git a/mode/forth.py b/mode/forth.py
index f7c6505..9864e73 100644
--- a/mode/forth.py
+++ b/mode/forth.py
@@ -21,7 +21,7 @@ class StringGrammar3(Grammar): rules = [PatternRule('data', r'[^)]+')]
 class ForthGrammar(Grammar):
     rules = [
         PatternRule('comment', r"\\(?: .*)?\n$"),
-        RegionRule('comment', r'\((?= |\n)', DataGrammar, r'\)'),
+        RegionRule('comment', r'\((?= |\n|$)', DataGrammar, r'\)'),
         NocaseRegionRule('comment', r'0 \[if\]', DataGrammar, r'\[(?:endif|then)\]'),
         RegionRule('string', r'[.cs]" ', StringGrammar2, r'"'),
         RegionRule('string', r'[.s]\\" ', StringGrammar2, r'"'),