Sebastolobus, the thornyheads, is a genus of marine ray-finned fish belonging to the subfamily Sebastinae, the rockfishes, part of the family Scorpaenidae.

[1] It is the type genus of the tribe Sebastolobini, one of two in the Sebastinae, a subfamily of the family Scorpaenidae.

[3] There are currently three recognized species in this genus:[4] Sebastolobus thornyheads have moderately compressed bodies with relatively large head armed with 8 pairs of robust spines along its top.

[4] Sebastolobus thornyheads are found in the northern Pacific Ocean in both the eastern and western parts with vagrants extending as far south as Costa Rica.

[4] Sebastolobus thornyheads are oviparous, unlike the rockfishes in the genus Sebastes and the females extrude gelatinous egg masses.