The Fly River water rat (Leptomys signatus) is a species of rodent in the family Muridae. It is found only in Papua New Guinea. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss.

• Musser, G. G.; Carleton, M. D. (2005). "Superfamily Muroidea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 894–1531. ISBN 978-0-8018-8221-0. OCLC 62265494.