diff --git a/config.h b/config.h
index 01bee41..617e27a 100644
--- a/config.h
+++ b/config.h
@@ -47,7 +47,7 @@ static const Rule rules[] = {
 	 */
 	/* class      instance    title       tags mask     isfloating   monitor */
 	{ "Gimp",     NULL,       NULL,       0,            1,           -1 },
-	{ "firefox",  NULL,       NULL,       1 << 1,       0,           -1 },
+	{ "Firefox",  NULL,       NULL,       1 << 1,       0,           -1 },
 	{ "discord",  NULL,       NULL,       1 << 2,       0,           -1 },
 	{ "Steam",    NULL,       NULL,       1 << 3,       0,           -1 },
 	{ "UE4Editor",    NULL,       NULL,       1 << 3,       0,           -1 },