All species have five arms and are native to shallow oceanic areas (the littoral zone) of cold to temperate parts of the Holarctic.

[2] Johannes Peter Müller and Franz Hermann Troschel worked on starfish systematics in 1840, renaming the genus Asteracanthion and splitting a number of new genera from it.

[1] Francis Jeffrey Bell listed 78 species in the genus in 1881, arranging them in some 16 unranked groupings (see artificial taxonomy).

Asterias, like most starfish genera in the order Forcipulatida, are recognisable externally by their pedicellariae, many thousands of tiny jaw-like structures on the skin which can snap shut to nip at prey or predators.

Internally, the exoskeleton also presents some diagnostic characters, such as the dorsal plates bearing only a single spine in their centre.