Eucithara unilineata is a small sea snail, a marine gastropod mollusk in the family Mangeliidae.

The body whorl, which exceeds half the total height, presents, on the side opposite to the outer lip, a convex profile, more rapidly acuminated below the middle.

The columella, weakly concave in its upper part, is furrowed in its entire length by numerous folds, very distinct but rather thin, which run along the edge in its width and In the interior.

Thickened on the last rib, it presents a sharp lip below which comes a large number of small well-marked folds, which appear as denticles.

The sinus, located below the suture, is small, obliquely and deeply lodged back in the callus which is prominent on the outer lip.