Phyllidia polkadotsa is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Phyllidiidae.
This species was described from the Hawaiian Islands.
This nudibranch has a yellow or orange coloured dorsum with large round black spots which are surrounded by a paler, translucent, ring. There are three longitudinal ridges along the back and small, scattered, tubercles.
This species feeds on a sponge.