Acanthodoris lutea, the orange-peel doris, is a species of nudibranch or sea slug, a shell-less marine opisthobranch gastropod mollusk in the family Onchidorididae. This species is the largest of the northeastern Pacific onchidorids. It is a common species, and it is very noticeable because of its bright coloration, which is aposematic. The species name "lutea" is a Latin word which means an orange-yellow color. The generic name, "acantho" comes from the Greek word meaning spiny, and "doris" is the name of an ancient Greek sea nymph.