Borsonia smithi is a species of sea snail, a marine gastropod mollusk in the family Borsoniidae.

In the lower ones the shell is slightly excavated below the suture, but otherwise regularly rounded, without nodules.

This latter is regularly attenuated towards the base and runs in the rather long, large canal, which in its basal part is free from lirae and only sculptured by fine and groovelike growth-lines.

The aperture is angularly ovate, with a moderately sharp angle above, ending below in a rather wide, slightly contorted siphonal canal.

The interior of the aperture is smooth, white, the whole columellar side with a strong layer of enamel.