Marginellidae, or the margin shells, are a taxonomic family of small, often colorful, sea snails, marine gastropod molluscs in the clade Neogastropoda.

The higher classification of the family Marginellidae has long been in a state of confusion.

Many popular works still treat all members of this family under the single genus Marginella, basing them primarily on superficial similarities of the shell.

Such information as did exist on the radulae and the external anatomy of the living animals was widely scattered in the scientific literature, and internal anatomical descriptions were not available until fairly recently.

In 2019 a new molecular phylogeny of marginelliform gastropods has been established by Fedosov A.E., Caballer Gutierrez M., Buge B., Sorokin P.V., Puillandre N., Bouchet P.[2] The shell of Marginellidae is usually small, but varies in different species from minute to medium-sized.