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

Phyllidia carlsonhoffi has a black body with small rounded yellow tubercles and more or less regularly distributed large conical yellow tubercles in the center of white rings.

The ventral surface is a pale cream color, with a median black line on the bottom of the foot sole.

This species has been found in western Pacific Ocean (Micronesia, Papua New Guinea and Fiji).

This nudibranch prefers shallow subtidal lagoons, on the reefs, and seaward slopes, at depths of 1–25 meters.