The Ngai Tahu Claims Settlement Act 1998 was an act of Parliament passed in New Zealand relating to Ngai Tahu. It was negotiated in part by Henare Rakiihia Tau.

Ngai Tahu, or Kai Tahu, is the principal Maori iwi (tribe) of the southern region of New Zealand, with its tribal authority, Te Runanga o Ngai Tahu (sometimes known as TRoNT), based in Christchurch and Invercargill. The iwi combines three groups, Kai Tahu itself, and Waitaha and Kati Mamoe who lived in the South Island prior to the arrival of Kai Tahu. The five primary hapu of the three combined groups are Kati Kuri, Ngati Irakehu, Kati Huirapa, Ngai Tuahuriri and Ngai Te Ruakihikihi. (Some people claim explicit descent from one or both of Waitaha and Kati Mamoe whanui, often in conjunction with Kai Tahu. However, others argue that due to conflict and intermarriage these groups have become incorporated into Kai Tahu, and are no longer distinct.)