Among the Haudenosaunee (the "Six Nations," comprising the Mohawk, Onondaga, Oneida, Cayuga, Seneca, and Tuscarora peoples) the Great Law of Peace (Mohawk: Kaianere’kó:wa), also known as Gayanashagowa, is the oral constitution of the Iroquois Confederacy. The law was written on wampum belts, conceived by Dekanawidah, known as the Great Peacemaker, and his spokesman Hiawatha. The original five member nations ratified this constitution near modern-day Victor, New York, with the sixth nation (the Tuscarora) being added in 1722.

The laws were first recorded and transmitted not in written language, but by means of wampum symbols that conveyed meaning. In a later era it was translated into English and various other accounts exist. The Great Law of Peace is presented as part of a narrative noting laws and ceremonies to be performed at prescribed times. The laws, called a constitution, are divided into 117 articles. The united Iroquois nations are symbolized by an eastern white pine tree, called the Tree of Peace. Each nation or tribe plays a delineated role in the conduct of government.

The Iroquois claim the events date back to the late 12th century (around 1190).