diff --git a/src/vim9class.c b/src/vim9class.c
index a91a4a5..94fe9e2 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -248,6 +248,16 @@
 	    break;
 	char_u *line = skipwhite(theline);
 
+	// Skip empty and comment lines.
+	if (*line == NUL)
+	    continue;
+	if (*line == '#')
+	{
+	    if (vim9_bad_comment(line))
+		break;
+	    continue;
+	}
+
 	char_u *p = line;
 	if (checkforcmd(&p, "endclass", 4))
 	{