Alycaeus gibbosulus is a species of small land snails with a gill and an operculum, terrestrial gastropod mollusks in the family Alycaeidae.

Near the aperture, it is briefly but strongly constricted, slightly smooth, barely deflected, and fitted with a thin tube about two to three millimeters long, which is sometimes almost fully immersed.

The aperture is circular and moderately wide, surrounded by a simple, slightly expanded margin in young specimens, and bilabiate in adults.

The operculum is solid, with a slightly convex, horny inner surface, submammillate at the center, and multi-spiral, featuring a transverse oval and eccentric muscular impression.

This species is presumably closely related to Alycaeus conformis, due to the similarity in the protoconch sculpture.