K'usilluni (Aymara k'usillu monkey, Ref Bertonio Teodoro Marka M., Curso Basico de Lengua Aymara, Nociones Basicas de Lengua Aymara -ni a suffix to indicate ownership, "the one with a monkey (or monkeys)", also spelled Kusilluni) is a mountain in the eastern extensions of the Apolobamba mountain range in Bolivia, about 4600 meters high.