Squalus crassispinus, the fatspine spurdog, is a dogfish of the family Squalidae, found on the continental shelf off the northern coast of Western Australia, at depths of 180 to 200 metres (590 to 660 ft).

Squalus crassispinus is a rare, small and slender dogfish with a broad head and short snout.

There is a broad, small medial barbel on the anterior nasal flaps.

The pectoral fin has a shallowly concave posterior margin.

Coloration is light grey above, paler below, with no white spots.