Nemesignis is a genus of sea slugs, aeolid nudibranchs, marine gastropod mollusks in the family Myrrhinidae with only one species, Nemesignis banyulensis.
The genus was originally named Nemesis by Furfaro & Mariottini in 2021, but being a junior homonym of the crustacean Nemesis, named in 1826 by Risso, the genus name of the nudibranch was replaced with Nemesignis.
This species is found in the Mediterranean Sea and adjacent Atlantic Ocean.