Collins' squirrel monkey (Saimiri collinsii) is a species of squirrel monkey endemic to Brazil. It had been considered a subspecies of the common squirrel monkey (S. sciureus) until a genetic study by Jessica Lynch Alfaro et al. elevated it to species status.
Male Collins' squirrel monkeys have a head and body length of about with a tail. Females have a head and body length of about with a tail. Collins' squirrel monkeys eat palm fruits, legumes, insects, bird eggs and occasionally lizards.