The red-capped tamarin, Saguinus pileatus, is a primate of the family of marmosets (Callitrichidae), a species of tamarin from South America who was once considered a subspecies of the Saguinus mystax (mystax S. pileatus). They are found in Brazil, on the eastern margin of the Tefé and Coari rivers. They are presumably related to the Moustached tamarin.