Северный остров Новой Зеландии Te Ika-a-Māui

One of the two main New Zealand islands
the island in New Zealand

The North Island, also officially named Te Ika a Māui, is one of the two main islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the world's 14th largest island, constituting 43% of New Zealand's land area. It has a population of which is % of New Zealand's residents, making it the most populous island in Polynesia and the 28th most populous island in the world. Twelve main urban areas (half of them officially cities) are in the North Island. From north to south, they are Whangārei, Auckland, Hamilton, Tauranga, Rotorua, Gisborne, New Plymouth, Napier, Hastings, Whanganui, Palmerston North, and New Zealand's capital city Wellington, which is located at the south west tip of the island.

Although the island has been known as the North Island for many years, the Māori name for it is Te Ika a Māui. On some 19th century maps, the North Island is named New Ulster, which was also a province of New Zealand that included the North Island. In 2009 the New Zealand Geographic Board found that, along with the South Island, the North Island had no official name. After a public consultation, the board officially named it North Island, or the aforementioned Te Ika a Māui, in October 2013. In prose, the two main islands of New Zealand are called the North Island and the South Island, with the definite article. It is also normal to use the preposition in rather than on, for example "Hamilton is in the North Island", "my mother lives in the North Island". Maps, headings, tables, and adjectival expressions use North Island without "the".

According to Māori mythology, the North and South Islands of New Zealand arose through the actions of the demigod Māui. Māui and his brothers were fishing from their canoe (the South Island) when he caught a great fish and pulled it right up from the sea. While he was not looking, his brothers fought over the fish and chopped it up. This great fish became the North Island, and thus a Māori name for the North Island is Te Ika a Māui ("The Fish of Māui"). The mountains and valleys are believed to have been formed as a result of Māui's brothers' hacking at the fish. During Captain James Cook's voyage between 1769 and 1770, Tahitian navigator Tupaia accompanied the circumnavigation of New Zealand. The maps described the North Island as "Ea Heinom Auwe" and "Aeheinomowe", which recognises the "Fish of Māui" element. Another Māori name that was given to the North Island, but is now used less commonly, is Aotearoa. Use of Aotearoa to describe the North Island fell out of favour in the early 20th century, and it is now a collective Māori name for New Zealand as a whole.

During the Last Glacial Period when sea levels were over 100 metres lower than present day levels, the North and South islands were connected by a vast coastal plain which formed at the South Taranaki Bight. During this period, most of the North Island was covered in thorn scrubland and forest, while the modern day Northland Peninsula was a subtropical rainforest. Sea levels began to rise 7,000 years ago, eventually separating the islands and linking the Cook Strait to the Tasman Sea. In the year to June 2020, the North Island gained 21,950 people from natural increase and 62,710 people from international migration, while losing 3,570 people from internal migration.

At the 2018 New Zealand census, 65.7% of North Islanders identified as of European ethnicity, 18.5% as Māori, 17.0% as Asian, 9.7% as Pasifika, 1.6% as Middle Eastern/Latin American/African, and 1.2% as another ethnicity (mainly 'New Zealander'). Totals add to more than 100% since people may identify with multiple ethnicities. The proportion of North Islanders born overseas is 29.3%. The most common foreign countries of birth are England (15.4% of overseas born residents), Mainland China (11.3%), India (10.1%), South Africa (5.9%), Australia (5.5%) and Samoa (5.3%).

The sub national GDP of the North Island was estimated at NZ$ 282.355 billion in 2021 (78% of New Zealand's national GDP).