If it's a Chinese wedding, parents can wear traditional clothes, such as Tang suit. The father is mainly dark and the mother is mainly red, but don't be too fancy to steal the limelight of the couple. If it is more modern or western-style, my father wears a dark suit and my mother wears a red dress, but not too bright. In fact, on the whole, it is ok to be generous and decent, without losing the identity of the owner or overshadowing the newcomers. Of course, it is better to dress festive on festive days.