Cethegus robustus is a species of mygalomorph spider in the family Euagridae. It is endemic to Australia. It was first described in 1984 by Australian arachnologist Robert Raven.
The species occurs in Far North Queensland in open forest habitats. The type locality is Chillagoe.
The spiders are fossorial, terrestrial predators. They construct curtain-like silk webs over their burrows.