Ratu Boko or Ratu Boko Palace is an archaeological site in Java. Ratu Boko is located on a plateau, about three kilometres south of Prambanan temple complex in Yogyakarta, Indonesia. The original name of this site is still unclear, however the local inhabitants named this site after King Boko, the legendary king mentioned in Roro Jonggrang folklore. In Javanese, Ratu Boko means "Stork King".
The site covers 16 hectares in two hamlets of the village of Bokoharjo and Prambanan, Sleman Regency. In striking contrast to other Classic-period sites in Central Java and Yogyakarta, which are remains of temples, Ratu Boko displays attributes of an occupation or settlement site, although its precise function is unknown. Probably the site was a palace complex which belonged to the kings of Sailendra or Mataram Kingdom that also built temples scattered across the Prambanan Plain. The argument was based on the fact that this complex was not a temple nor building with religious nature, but a fortified palace instead which evidence of a remnant of fortified walls and the dry moat of defensive structures. The remains of settlements also founds in Ratu Boko vicinity.