Borsonia timorensis is a species of sea snail, a marine gastropod mollusc in the family Borsoniidae.

(Original description) The thin shell has an elongately fusiform shape, with a rather short siphonal canal.

The finer sculpture consists of fine and coarse growth striae and spiral ones, stronger below the suture, across the convex ribbed part, fainter near the base.

The peristome is thin, with a wide, shallow sinus, just below the suture, then strongly protracted.

The columellar margin is rather straight, with a faint fold at its upper half, not very conspicuous in the front view, with a rather thin, smooth layer of enamel.