Cystiscidae is a taxonomic family of small sea snails, marine gastropod mollusks or micromollusks.

The shell is minute to large, either white, uniformly colored, or patterned; the surface is smooth, sculptured, or axially costate; the spire is flat to immersed, or low to tall; the protoconch is paucispiral; the lip is thickened, smooth or denticulate; an external varix is present or absent; a siphonal notch is present or absent; a posterior notch is present or absent; the columella is multiplicate, internal whorls cystiscid or modified cystiscid type.

Proboscis pleurembolic; jaws absent; typical radular sac present.

The family was erected by William Stimpson for a single included species based on unusual features of the head and radula.

Coan (1965)[2] recognized this group as a subfamily, but he did not include such genera as Gibberula, Persicula, and Canalispira.