The Javan Hawk-eagle, Nisaetus bartelsi (earlier under Spizaetus) is a medium-sized, approximately 61cm long, dark brown raptor in the family Accipitridae. It has a long crest, rufous head and neck, and heavily barred black below. The crest is black with white tip. Both sexes are similar. The young is duller and has unmarked underparts.

An Indonesian endemic, the Javan Hawk-eagle is distributed in humid tropical forests of Java. Because of the plumages variability of Spizaetus eagle, the Javan Hawk-eagle was not recognised as a full species until 1953.

One of the rarest of all raptors, the Javan Hawk-eagle is believed to be a monogamous species. The female usually lays one egg in nest high on top of forest trees. The diet consists mainly of birds, lizards, fruit bats and mammals.

The Javan Hawk-eagle is the national bird of Indonesia. The scientific name commemorates Hans Bartels.

Due to ongoing habitat loss, small population size, limited range and hunting in some areas, the Javan Hawk-eagle is evaluated as Endangered on the IUCN Red List of Threatened Species. It is listed on Appendix II of CITES.