Liocranium is a small genus of marine ray-finned fishes, waspfishes belonging to the subfamily Tetraroginae, which is classified as part of the family Scorpaenidae, the scorpionfishes and their relatives.

Liocranium was first described as a genus in 1903 by the Australian ichthyologist James Douglas Ogilby when he described a new species of waspfish from Queensland he called Liocranium praepositum and placed in a new monotypic genus.

[2] The genus name liocranium is a compound of leios, meaning "smooth", and cranium, which means "skull", presumed to refer to the head of L. praepositum which has no skin flaps or tentacles.

[5] Liocranium has the following 2 species classified within it:[2] Liocranium waspfishes are characterised by having the origin of the dorsal fin being clearly in front of a vertical line running from the rear of the orbit.

There are no teeth on the palatine bone, There are many, small cycloid scales covering the flanks.