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.

[2][3] Male Collins' squirrel monkeys have a head and body length of about 38 cm (15 in) with a 37.6 cm (14.8 in) tail.

[2] Females have a head and body length of about 27 cm (11 in) with a 41.3 cm (16.3 in) tail.

[2] Collins' squirrel monkeys eat palm fruits, legumes, insects, bird eggs and occasionally lizards.