Clavus obliquicostatus is a species of sea snail, a marine gastropod mollusk in the family Drilliidae.
The length of the shell attains 33 mm. The longitudinal ribs are oblique, narrow, a little waved, and obtusely pointed on the periphery. A few revolve astride at the base of the body whorl. The shell is yellowish white, spotted and maculated with chestnut.
This marine species occurs off New Caledonia and Papua New Guinea