Phyllidiella rosans is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Phyllidiidae.

[2] This species was collected in Tahiti by Andrew Garrett and sent to both William Harper Pease and Rudolph Bergh.

Reports of this species from the Maldives, Tanzania and other Indian Ocean localities may be a distinct species.

[3][4] This nudibranch has a black dorsum with longitudinal pink ridges.

[4] This species feeds on a yellow sponge.