Vieira's titi monkey (Plecturocebus vieirai ) is a species of titi, a type of New World monkey, from central-northern Brazil.
Plecturocebus vieirai is named after Professor Carlos Octaviano da Cunha Vieira (1897‑1958), a Brazilian mammalogist and former Curator of the Mammal Collection at the Museum of Zoology of the University of São Paulo (MZUSP), Brazil.