The Rondon's marmoset (Mico rondoni), also known as the Rondônia marmoset, is a new species of marmoset from the family Callitrichidae found in the south-western Amazon in Brazil. It is endemic to the state of Rondônia, and its range bordered by the Rio Mamoré, Rio Madeira, Rio Ji-Paraná, Serra dos Pacaás Novos and possibly Bolivia. It was only described in 2010, and its name refers to the famous Amazonian explorer Cândido Rondon. Prior to its description, it was included in Emilia's marmoset (Mico emiliae).