Ocnosispa armata is a species of beetle of the family Chrysomelidae. It is found in Paraguay.
Adults are broadly elongate, scarcely dilated behind, subdepressed and fulvous. Three vittae on the thorax and the elytra are obscure rufo-fuscous with a metallic green reflexion. Each elytron has eight pale fulvous spots.
No host plant has been documented for this species.