It consists of two families: the monotypic Australiteuthis and the diverse and commercially important Loliginidae (~50 species).

Some of the most obvious differences are found in the structure of the eyes: those of myopsid squids lack a secondary eyelid and are instead covered by a transparent corneal membrane, the opening of which is reduced to a microscopic anterior pore in most species.

The carpal ("wrist") portion of the tentacular club lacks a locking apparatus, and a tentacle pocket is present on the head.

An internalised shell is present in the form of a well-developed gladius, which is located dorsally within the mantle and extends for almost its entire length.

[4][5] In turn, they are considered prey items by virtually all marine predators, including birds.