Iwi (Māori pronunciation: [ˈiwi] ) are the largest social units in New Zealand Māori society. In Māori iwi roughly means "people" or "nation",   and is often translated as "tribe",  or "a confederation of tribes". The word is both singular and plural in the Māori language, and is typically pluralised as such in English.
Iwi groups trace their ancestry to the original Polynesian migrants who, according to tradition, arrived from Hawaiki. Some iwi cluster into larger groupings that are based on whakapapa (genealogical tradition) and known as waka (literally "canoes", with reference to the original migration voyages). These super-groupings generally serve symbolic rather than practical functions. In pre-European times, most Māori were allied to relatively small groups in the form of hapū ("sub-tribes")  and whānau ("family").  Each iwi contains a number of hapū; among the hapū of the Ngāti Whātua iwi, for example, are Te Uri-o-Hau, Te Roroa, Te Taoū, and Ngāti Whātua-o-Ōrākei. Māori use the word rohe to describe the territory or boundaries of iwi. 
In modern-day New Zealand, iwi can exercise significant political power in the management of land and of other assets. For example, the 1997 Treaty of Waitangi settlement between the New Zealand Government and Ngāi Tahu, compensated that iwi for various losses of the rights guaranteed under the Treaty of Waitangi of 1840. As of 2019 [update] the tribe has collective assets under management of $1.85 billion.  Iwi affairs can have a real impact on New Zealand politics and society. A 2004 attempt by some iwi to test in court their ownership of the seabed and foreshore areas polarised public opinion (see New Zealand foreshore and seabed controversy).
In Māori and in many other Polynesian languages, iwi literally means "bone"  derived from Proto-Oceanic *suRi₁ meaning "thorn, splinter, fish bone".  Māori may refer to returning home after travelling or living elsewhere as "going back to the bones" — literally to the burial-areas of the ancestors. Māori author Keri Hulme's novel The Bone People (1985) has a title linked directly to the dual meaning of bone and "tribal people".
Many iwi names begin with Ngāti or with Ngāi (from ngā āti and ngā ai respectively, both meaning roughly "the offspring of"). Ngāti has become a productive morpheme in New Zealand English to refer to groups of people: examples are Ngāti Pākehā (Pākehā as a group), Ngāti Poneke (Māori who have migrated to the Wellington region), and Ngāti Rānana (Māori living in London). Ngāti Tūmatauenga ("Tribe of Tūmatauenga", the god of war) is the official Māori-language name of the New Zealand Army, and Ngā Opango ("Black Tribe") is a Māori-language name for the All Blacks.
In the southern dialect of Māori, Ngāti and Ngāi become Kāti and Kāi, terms found in such iwi as Kāti Māmoe and Kāi Tahu (also known as Ngai Tahu).
Each iwi has a generally recognised territory ( rohe ), but many of these overlap, sometimes completely.  This has added a layer of complication to the long-running discussions and court cases about how to resolve historical Treaty claims. The length of coastline emerged as one factor in the final (2004) legislation to allocate fishing-rights in settlement of claims relating to commercial fisheries.
Iwi can become a prospective vehicle for ideas and ideals of self-determination and/or tino rangatiratanga . Thus does the Māori Party mention in the preamble of its constitution "the dreams and aspirations of tangata whenua to achieve self-determination for whānau, hapū and iwi within their own land".  Some Tūhoe envisage self-determination in specifically iwi-oriented terms. 
Increasing urbanisation of Māori has led to a situation where a significant percentage do not identify with any particular iwi. The following extract from a 2000 High Court of New Zealand judgment discussing the process of settling fishing rights illustrates some of the issues:
... 81 per cent of Maori now live in urban areas, at least one-third live outside their tribal influence, more than one-quarter do not know their iwi or for some reason do not choose to affiliate with it, at least 70 per cent live outside the traditional tribal territory and these will have difficulties, which in many cases will be severe, in both relating to their tribal heritage and in accessing benefits from the settlement. It is also said that many Maori reject tribal affiliation because of a working-class unemployed attitude, defiance and frustration. Related but less important factors, are that a hapu may belong to more than one iwi, a particular hapu may have belonged to different iwi at different times, the tension caused by the social and economic power moving from the iwi down rather than from the hapu up, and the fact that many iwi do not recognise spouses and adoptees who do not have kinship links. 
In the 2006 census, 16 per cent of the 643,977 people who claimed Māori ancestry did not know their iwi. Another 11 per cent did not state their iwi, or stated only a general geographic region, or merely gave a waka name.  Initiatives like the Iwi Helpline are trying to make it easier for people to identify their iwi,  and the proportion who "don't know" dropped relative to previous censuses. 
Some established pan-tribal organisations may[ according to whom? ] exert influence across iwi divisions.[ citation needed ] The Rātana Church, for example, operates across iwi divisions, and the Māori King Movement, though principally congregated around Waikato/Tainui, aims to transcend some iwi functions in a wider grouping.[ citation needed ]
Many iwi operate or are affiliated with media organisations. Most of these belong to Te Whakaruruhau o Nga Reo Irirangi Māori (the National Māori Radio Network), a group of radio stations which receive contestable Government funding from Te Māngai Pāho (the Māori Broadcast Funding Agency) to operate on behalf of iwi and hapū. Under their funding agreement, the stations must produce programmes in the local Māori language and actively promote local Māori culture. 
A two-year Massey University survey of 30,000 people published in 2003 indicated 50 per cent of Māori in National Māori Radio Network broadcast areas listened to an iwi station.  An Auckland University of Technology study in 2009 suggested the audience of iwi radio stations would increase as the growing New Zealand Māori population tried to keep a connection to their culture, family history, spirituality, community, language and iwi. 
The Victoria University of Wellington Te Reo Māori Society campaigned for Māori radio, helping to set up Te Reo o Poneke, the first Māori-owned radio operation, using airtime on Wellington student-radio station Radio Active in 1983.  Twenty-one iwi radio stations were set up between 1989 and 1994, receiving Government funding in accordance with a Treaty of Waitangi claim.  This group of radio stations formed various networks, becoming Te Whakaruruhau o Nga Reo Irirangi Māori. 
The Maori Party is born of the dreams and aspirations of tangata whenua to achieve self-determination for whānau, hapū and iwi within their own land; to speak with a strong, independent and united voice; and to live according to kaupapa handed down by our ancestors. The vision for the Maori Party will be based on these aspirations [...]
Calls from Maori activist Tame Iti for self-government arrangements for the Tuhoe tribe similar to those Wales, Scotland and Northern Ireland have in the UK have been backed by a leader likely to negotiate the tribe's Treaty settlement. ... While other iwi have focused on economic transfer of assets as a way of achieving tino rangatiratanga or self-determination, Tuhoe have spelled out their intention to negotiate constitutional issues.
Te Rauparaha was a Māori rangatira (chief) and war leader of the Ngāti Toa tribe who took a leading part in the Musket Wars, receiving the nickname "the Napoleon of the South". He was influential in the original sale of land to the New Zealand Company and was a participant in the Wairau Affray in Marlborough.
The Musket Wars were a series of as many as 3,000 battles and raids fought throughout New Zealand among Māori between 1807 and 1837, after Māori first obtained muskets and then engaged in an intertribal arms race in order to gain territory or seek revenge for past defeats. The battles resulted in the deaths of between 20,000 and 40,000 people and the enslavement of tens of thousands of Māori and significantly altered the rohe, or tribal territorial boundaries, before the signing of the Treaty of Waitangi in 1840.
Ngāi Tahu, or Kāi Tahu, is the principal Māori iwi (tribe) of the South Island. Its takiwā is the largest in New Zealand, and extends from the White Bluffs / Te Parinui o Whiti, Mount Mahanga and Kahurangi Point in the north to Stewart Island / Rakiura in the south. The takiwā comprises 18 rūnanga corresponding to traditional settlements. According to the 2018 census an estimated 74,082 people affiliated with the Kāi Tahu iwi.
Ngāti Porou is a Māori iwi traditionally located in the East Cape and Gisborne regions of the North Island of New Zealand. Ngāti Porou is affiliated with the 28th Maori Battalion, It also has the second-largest affiliation of any iwi, behind Ngāpuhi with an estimated 92,349 people according to the 2018 census. The traditional rohe or tribal area of Ngāti Porou extends from Pōtikirua and Lottin Point in the north to Te Toka-a-Taiau in the south. The Ngāti Porou iwi also comprises 58 hapū (sub-tribes) and 48 mārae.
Ngāti Kahungunu is a Māori iwi located along the eastern coast of the North Island of New Zealand. The iwi is traditionally centred in the Hawke's Bay and Wairārapa regions. The Kahungungu iwi also comprises 86 hapū (sub-tribes) and 90 mārae.
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 Kaikoura and Hokitika in the south. Ngāti Toa remains a small iwi with a population of only about 4500. 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.
In Māori and New Zealand English, a hapū functions as "the basic political unit within Māori society". A Māori person can belong to or have links to many hapū. Historically, each hapū had its own chief and normally operated independently of its iwi (tribe).
Claims and settlements under the Treaty of Waitangi have been a significant feature of New Zealand politics since the Treaty of Waitangi Act 1975 and the Waitangi Tribunal that was established by that act to hear claims. Successive governments have increasingly provided formal legal and political opportunity for Māori to seek redress for what are seen as breaches by the Crown of guarantees set out in the Treaty of Waitangi. While it has resulted in putting to rest a number of significant longstanding grievances, the process has been subject to criticisms including those who believe that the redress is insufficient to compensate for Māori losses. The settlements are typically seen as part of a broader Māori Renaissance.
Ngāti Awa is a Māori iwi (tribe) centred in the eastern Bay of Plenty Region of New Zealand. It is made of 22 hapū (subtribes), with 15,258 people claiming affiliation to the iwi in 2006. The Ngāti Awa people are primarily located in towns on the Rangitaiki Plain, including Whakatāne, Kawerau, Edgecumbe, Te Teko and Matatā. Two urban hapū also exist in Auckland and Wellington.
Ngāti Ruanui is a Māori iwi traditionally based in the Taranaki region of New Zealand. In the 2006 census, 7,035 people claimed affiliation to the iwi. However, most members now live outside the traditional areas of the iwi.
Te Āti Awa is a Māori iwi with traditional bases in the Taranaki and Wellington regions of New Zealand. Approximately 17,000 people registered their affiliation to Te Āti Awa in 2001, with around 10,000 in Taranaki, 2,000 in Wellington and around 5,000 of unspecified regional location.
Muaūpoko is a Māori iwi on the Kapiti Coast of New Zealand.
Ngāi Tāmanuhiri is a Māori iwi of New Zealand and were formerly known by the name of Ngai Tahu, and Ngai Tahu-po respectively. They are descendants of Tahu-nui who is also the eponymous ancestor of the Kai Tahu iwi of Te Waipounamu.
Ngāti Hauā is a Māori iwi of the eastern Waikato of New Zealand. It is part of the Tainui confederation. Its traditional area includes Matamata, Cambridge, Maungakawa, the Horotiu district along the Waikato River and the Maungatautari district, and its eastern boundary is the Kaimai Range. Leaders of the tribe have included Te Waharoa, his son Wiremu Tamihana and Tamihana's son Tupu Taingakawa. The tribe has played a prominent role in the Māori King Movement, with Tamihana and descendants being known as the "Kingmakers".
Ngāti Mutunga is a Māori iwi (tribe) of New Zealand, whose original tribal lands were in north Taranaki. They migrated from Taranaki, first to Wellington, and then to the Chatham Islands in the 1830s. The rohe of the iwi include Wharekauri, Te Whanga Lagoon and Waitangi on Chatham Island, and Pitt Island, also part of the Chatham Islands. The principal marae are at Urenui in Taranaki, and on the Chatham Islands.
Ngāti Tama is a historic Māori iwi of present-day New Zealand which whakapapas back to Tama Ariki, the chief navigator on the Tokomaru waka. The iwi of Ngati Tama is located in north Taranaki around Poutama. The Mōhakatino river marks their northern boundary with the Tainui and Ngāti Maniapoto iwi. Titoki marks the southern boundary with Ngati Mutunga. The close geographical proximity of Tainui's Ngati Toa of Kawhia and Ngati Mutunga explains the long, continuous, and close relationship among the three Iwi.
Rongowhakaata is a Māori iwi of the Gisborne region of New Zealand.
Taranaki (Tuturu) is a Māori iwi of New Zealand.
Te Whakaruruhau o Ngā Reo Irirangi Māori is a New Zealand radio network consisting of radio stations that serve the country's indigenous Māori population. Most stations receive contestable government funding from Te Māngai Pāho, the Māori Broadcast Funding Agency, to operate on behalf of affiliated iwi (tribes) or hapū (sub-tribes). Under their funding agreement, the stations must produce programmes in the Māori language, and must actively promote Māori culture.
This timeline sets out intertribal battles involving Māori people in what is now New Zealand.