Speaking in Oslo, committee chair Jørgen Watne Frydnes announced the award, noting that Pillay's career embodied the principle that international law is essential to resolving conflicts. In a news release, the committee stated: "At a time when the number of wars and conflicts is rising, and when judges and institutions of international law are under political attack, the Nobel committee wishes to issue a reminder that the ability to resolve conflicts without force or violence is dependent on the international rule of law."
The committee added: "An international legal system in which war criminals are held to account and the victims of abuse see justice served is a precondition for a peaceful world."
Efforts to reach Pillay by phone were not immediately successful.
The prize comes as part of the annual Nobel announcements. Earlier this week, Canadian poet Anne Carson was awarded the Nobel Prize in Literature.