Cetopsidium is a genus of catfishes (order Siluriformes) of the family Cetopsidae.

A lateral line extending to over the posterior portion of the base of the anal fin but falling short of the caudal peduncle is also unique in this genus; the lateral line is usually longer than this, though it is shorter in two species of Denticetopsis.

Cetopsidium species have mental barbels extending posteriorly beyond the rear margin of the opercle and a deeply forked, symmetrical caudal-fin margin with the tips of the lobes slightly blunt or rounded.

[1] Sexual dimorphism is observed in C. ferreirai, C. morenoi, C. orientale, and C. pemon, but not in C. minutum or C. roae.

Presumed mature males have the first ray of the dorsal and pectoral fins extended into filaments except in C. ferreirai.