Alcyna acia is a species of small sea snail, a marine gastropod mollusk or micromollusk in the family Trochidae, the top snails.

[1] The size of the shell attains 3mm.

This marine species is endemic to Australia and occurs off Southern Australia and West Australia.

This marine species tends to live in places with a sea surface temperature of 15–25 °C (59–77 °F).

This Trochidae-related article is a stub.