diff --git a/SPEC.md b/SPEC.md
index 265f306..eb52bc2 100644
--- a/SPEC.md
+++ b/SPEC.md
@@ -338,5 +338,6 @@ bom := '\u{FFEF}'
 unicode-space := See Table (All White_Space unicode characters which are not `newline`)
 
 single-line-comment := '//' ^newline+ newline
-multi-line-comment := '/*' ('*' [^\/] | [^*])* '*/'
+multi-line-comment := '/*' (commented-block | multi-line-comment) '*/'
+commented-block := ('*' [^\/] | [^*])*
 ```