The New Zealand Wars (Māori: Ngā pakanga o Aotearoa) took place from 1845 to 1872 between the New Zealand colonial government and allied Māori on one side, and Māori and Māori-allied settlers on the other. Though the wars were initially localised conflicts triggered by tensions over disputed land purchases (by European settlers from Māori), they escalated dramatically from 1860 as the government became convinced it was facing united Māori resistance to further land sales and a refusal to acknowledge Crown sovereignty. The colonial government summoned thousands of British troops to mount major campaigns to overpower the Kīngitanga (Māori King) movement and also conquest of farming and residential land for British settlers. Later campaigns were aimed at quashing the Pai Mārire religious and political movement, which was strongly opposed to the conquest of Māori land and eager to strengthen Māori identity. Māori religious movements that promoted pan-Māori identity played a major role in the Wars.

At the peak of hostilities in the 1860s, 18,000 British Army troops, supported by artillery, cavalry and local militia, battled about 4,000 Māori warriors in what became a gross imbalance of manpower and weaponry. Although outnumbered, the Māori were able to withstand their enemy with techniques that included anti-artillery bunkers and the use of carefully placed pā (fortified villages) that allowed them to block their enemy's advance and often inflict heavy losses, yet quickly abandon their positions without significant loss. Guerrilla-style tactics were used by both sides in later campaigns, often fought in dense bush. Over the course of the Taranaki and Waikato campaigns, the lives of about 1,800 Māori and 800 Europeans were lost, and total Māori losses over the course of all the wars may have exceeded 2,100.

Violence over land ownership broke out first in the Wairau Valley in the South Island in June 1843, but rising tensions in Taranaki eventually led to the involvement of British military forces at Waitara in March 1860. The war between the government and Kīngitanga Māori spread to other areas of the North Island, with the biggest single campaign being the invasion of the Waikato in 1863–1864, before hostilities concluded with the pursuits of Riwha Tītokowaru in Taranaki (1868–1869) and Rangatira (chief) Te Kooti Arikirangi Te Turuki on the east coast (1868–1872).

Although Māori were initially fought by British Army forces, the New Zealand government developed its own military force, including local militia, rifle volunteer groups, the specialist Forest Rangers and kūpapa (pro-government Māori). As part of broader Australian involvement in the wars, the Colony of Victoria deployed its naval forces, and at least 2,500 volunteers formed contingents that crossed the Tasman Sea and integrated with the New Zealand militia. The government also responded with legislation to imprison Māori opponents and confiscate expansive areas of the North Island for sale to settlers, with the funds used to cover war expenses; punitive measures that on the east and west coasts provoked an intensification of Māori resistance and aggression.

The New Zealand Wars were previously referred to as the Land Wars or the Māori Wars, and an earlier Māori-language name for the conflict was Te riri Pākehā ("the white man's anger"). Historian James Belich popularised the name "New Zealand Wars" in the 1980s, although according to Vincent O'Malley, the term was first used by historian James Cowan in the 1920s.

The 1840 English language version of the Treaty of Waitangi guaranteed that individual Māori iwi (tribes) should have undisturbed possession of their lands, and property taonga (Māori for 'treasures') in return for becoming British subjects, selling land to the government only (the right of pre-emption) and surrendering sovereignty to the British Crown. In the Māori language version of the Treaty, however, the word "sovereignty" was translated as kawanatanga which was a new word meaning "governance". This led to considerable disagreement over the meaning of the Treaty. Some Māori wanted to sign to consolidate peace and in hopes of ending the long intertribal Musket Wars (1807–1845) others wanted to keep their tino rangatiratanga, such as Tūhoe in Te Urewera.

All pre-treaty colonial land-sale deals had taken place directly between two parties. In the early period of contact, Māori had generally sought trade with Europeans. The British and the French had established mission stations, and missionaries had received land from iwi for houses, schools, churches, and farms.

Traders, Sydney businessmen and the New Zealand Company had bought large tracts of land before 1840. The Treaty of Waitangi included the right of Crown pre-emption on land sales, and the New Zealand colonial government, pressured by immigrant European settlers, tried to speed up land sales to provide farmland. This met resistance from the Kīngitanga (Māori King) movement that emerged in the 1850s and opposed further European encroachment.