The National Provincial Championship (NPC) is an annual, men's round-robin rugby union competition organised by New Zealand Rugby. First played in 1976, it is the second highest level of professional rugby in New Zealand. The Ranfurly Shield is also played for during the season. In 2021, Bunnings became the naming rights sponsor and the competition has been known as the Bunnings NPC since. A concurrent women's tournament is also held, called the Farah Palmer Cup.

Following the 2005 season the league was restructured into a two-tier competition. The National Provincial Championship would include professional and semi-professional players, and consist of the top fourteen financial and sporting best performing regional teams. For sponsorship reasons it was rebranded as the Air New Zealand Cup. The remaining teams would form an amateur competition known as the Heartland Championship.

Twenty-nine teams have competed since the inception of the competition in 1976. Auckland are historically the most successful union with seventeen titles and Canterbury is the most successful team during the professional era, having won ten from twelve finals. Eight other teams have won titles from both periods: Wellington (6), Waikato (3), Otago (2), Taranaki (2), Tasman (2), Bay of Plenty (1), Counties Manukau (1) and Manawatu (1).

The first form of competition came in 1904 with the introduction of the Ranfurly Shield as a challenge trophy. Each year, fixtures were arranged in Wellington during the annual meeting of the New Zealand Rugby Football Union, where an elected representative from each provincial union would propose dates and opponents that ideally avoided conflicts with local club competitions. Across the country, neighbouring regions organised regular matches for challenge trophies. One of the most prestigious competitions, the Hanan Shield, was established in 1946 by Timaru's former mayor, A.E.S. Hanan, and was contested by Mid Canterbury, South Canterbury, and North Otago. Another significant trophy, the Seddon Shield, was first challenged in 1906. Named after former New Zealand premier Richard Seddon, it featured representative teams from Buller, Nelson Bays, Marlborough, and the West Coast. In the North Island, starting in the King Country and moving north, eleven teams competed for the Coronation Shield.

Given the numerous competitions across New Zealand, there was a clear need for a national tournament. In 1972, Barry Smith proposed an inter-provincial competition to the Auckland Rugby Union. After gaining approval, the proposal was brought to the New Zealand Rugby Football Union's annual conference in early 1974. It included an overview of the scheme, addressing finance, travel, sponsorship opportunities, implications for club and sub-union competitions, traditional representative matches, international laws and Sunday play. Following discussions in October 1975, modifications were made and ultimately accepted by all provinces. Radio New Zealand secured sponsorship rights worth NZD 100,000 and helped market the new competition, later joined by Lion Breweries, National Mutual, and Air New Zealand.

Teams were divided into two divisions based on their performance over the previous five years. The premier division included Auckland, Bay of Plenty, Canterbury, Counties, Hawke's Bay, Manawatu, Marlborough, North Auckland, Otago, Southland, and Wellington, determined by a ranking system. The remaining provinces, Buller, East Coast, Horowhenua, King Country, Mid Canterbury, Nelson Bays, North Otago, Poverty Bay, South Canterbury, Taranaki, Thames Valley, Waikato, Wairarapa Bush, Wanganui and the West Coast were split into North Island and South Island sub-divisions, with the potential for promotion to the top division.

Between 1980 and the early 2000s, Auckland experienced a golden era, dominating competitions and consistently retaining the Ranfurly Shield. During this time, they reached eighteen finals, finishing as runners-up multiple times, and secured over half of the available competition titles, totaling fifteen. This remarkable run included a record sixty-one Ranfurly Shield defenses, five South Pacific Championship titles, and recognition as the Halberg Awards Team of the Year in 1992.

Canterbury emerged as the only team to consistently challenge Auckland's supremacy, with several matches becoming historic. The 1985 clash, where Auckland ended Canterbury's record-equalling streak of twenty-five matches, was famously dubbed the "Match of the Century." In front of a record crowd of 52,000 at Lancaster Park, Canterbury nearly staged a stunning comeback from a 24–0 half-time deficit, but Auckland held on to win 28–23, setting a new benchmark with sixty-one consecutive defences over eight years.