Ngāti Toa, Ngāti Toarangatira or Ngāti Toa Rangatira, is a Māori iwi (tribe) based in the southern North Island and in the northern South Island of New Zealand. Its rohe extends from Whanganui in the north, Palmerston North in the east, and Kaikōura and Hokitika in the south. Ngāti Toa remains a small iwi with a population of only about 9000. The iwi is centred around Porirua, Plimmerton, Kāpiti, Blenheim and Arapaoa Island. It has four marae: Takapūwāhia and Hongoeka in Porirua City, and Whakatū and Wairau in the north of the South Island. Ngāti Toa's governing body has the name Te Rūnanga o Toa Rangatira.

The South Island, also named Te Waipounamu in Māori, is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, and to the south and east by the Pacific Ocean. The South Island covers 150,437 square kilometres (58,084 sq mi), making it the world's 12th-largest island, constituting 56% of New Zealand's land area. At low altitude, it has an oceanic climate.