Oenopota violacea is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.

[1] It is extremely difficult to characterise this species, because both its form and sculpture are more variable than in any other of the whole genus.

The typical shell has, thus, very prominent spiral ribs devoid of other sculpture than lines of growth, whilst the varieties violacea and cylindracea, frequently, have quite prominent axial ribs, and these are invariably – even if they only occur as lines of growth – curved.

The most characteristic feature is the, not very long, cauda, and the deep wide siphonal canal.

[2] This species occurs in Northeast Atlantic Ocean and off the British Isles at depths between 80 m and 505 m