Weddell's saddle-back tamarin (Leontocebus weddelli) is a species of saddle-back tamarin, a type of small monkey from South America. Weddell's saddle-back tamarin was formerly considered to be a subspecies of the brown-mantled tamarin, L. fuscicollis. It lives in Brazil, Bolivia and Peru, with the type locality being in Bolivia.
There are 3 subspecies:
Males have a head and body length of about and females have a head and body length of about . The tail is between and long. Males weigh about and females weight about .
Its diet consists of fruits, gums, nectar, insects and other small animals. It lives in various types of groups, including single-adult male, single adult female groups, multi-male, multi-female groups, single-male, multi-female groups and single female, multi male groups. Females sometimes remain in their natal group. It associates with the emperor tamarin, the red-bellied tamarin and Goeldi's marmoset.
The IUCN rates it as least concern from a conservation standpoint.