Ithycythara psila is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.

(Original description) This is a shell of moderate size, slender, rather thick, very plain, yellowish white, with a dull, lusterless surface.

A single rounded thread revolves on the periphery at the shoulder of the whorls, scarcely visible on the interspaces, but forming conspicuous, oblong nodules on the ribs.

The protoconch is rather large, composed of 2½ regularly coiled, nearly smooth, somewhat shining whorls, the second having a row of minute nodules or beads on the periphery.

The outer lip is thin, nearly straight, broadly rounded anteriorly, with a decided sinus just below the suture.