A new species of eurysquilloid stomatopod, Eurysquilla petronioi sp. nov., is described from the tropical western Atlantic. Eurysquilla petronioi sp. nov. is the fourteenth species of the genus to be recognized worldwide, the fifth species from the western Atlantic and the second from Brazilian waters. It is most closely related to E. maiaguesensis from Puerto Rico, but differs chiefly in having an unarmed versus apically spinous rostral plate and 6 or 7 rather than 8–10 teeth on dactylus of raptorial claw. A key to the species of the genus is provided.