Mexichromis festiva is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusc in the family Chromodorididae.

[2] This species was described from Port Jackson, Australia.

[3] Mexichromis festiva is a white chromodorid nudibranch with raised pink spots on the mantle.

The edge of the mantle has a broken yellow line superimposed on an opaque white margin.

The outer half of the rhinophores is pink.