Facelina bostoniensis is a species of sea slug, an aeolid nudibranch in the family Facelinidae.

The body of Facelina bostoniensis is translucent white with a pink coloured hue around the mouth.

There are some patches of white pigment on the head, between the rhinophores and down the tail of the animal.

[3] Commonly found in tidepools on the lower shore and amongst hydroids in fast-flowing water as well as in very sheltered muddy areas.

Facelina bostoniensis feeds on a variety of hydroids and may attack and eat other aeolid nudibranchs.