2017 New Zealand general election

The 2017 New Zealand general election took place on Saturday 23 September 2017 to determine the membership of the 52nd New Zealand Parliament. The previous parliament was elected on 20 September 2014 and was officially dissolved on 22 August 2017. Voters elected 120 members to the House of Representatives under New Zealand's mixed-member proportional (MMP) voting system, a proportional representation system in which 71 members were elected from single-member electorates and 49 members were elected from closed party lists. Around 3.57 million people were registered to vote in the election, with 2.63 million (79.8%) turning out. Advance voting proved popular, with 1.24 million votes cast before election day, more than the previous two elections combined.

Prior to the election, the centre-right National Party, led by Prime Minister Bill English, had governed since 2008 in a minority government with confidence and supply from the Māori, ACT and United Future parties. It was the first election for English as incumbent prime minister, having replaced John Key on 12 December 2016 and the first since 1975 where both major parties had leadership changes. The main opposition parties to the National government were Labour (the official opposition), led by Jacinda Ardern, the Green Party, and New Zealand First.

The National Party won a plurality of the seats with 56, down from 60 in 2014. Labour made large gains following Jacinda Ardern becoming the party leader seven weeks prior to the election, increasing its representation from 32 to 46 seats. Labour was the only parliamentary party to gain support but a large portion came at the expense of the Green Party, who lost almost half their seats (dropping from 14 to 8) following co-leader Metiria Turei's resignation over self-admitted benefit and electoral fraud. The anti-immigration populist party New Zealand First won 9 seats, down from 12 in 2014. ACT retained its one seat. Election-night counts had National with 58 seats, Labour with 45 seats, and the Greens with 7 seats, but when special votes were counted, National lost one list seat each to the Greens and Labour.

The election saw five parties return to Parliament, down from seven in 2014 and the lowest number since the introduction of MMP in 1996. Māori Party co-leader Te Ururoa Flavell lost his seat of Waiariki and, with the party's vote count being below the threshold of 5%, they also lost their list MP, co-leader Marama Fox, and departed Parliament. United Future leader and sole MP Peter Dunne retired from politics during the campaign due to poor polling in his electorate of Ōhāriu and his successor failed to win the seat. The party voted to dissolve less than two months later.

Even with support partner ACT retaining its sole seat, the existing National minority government were short of the 61 seats needed to govern, and Bill English declared that the arrangement would not be continued. New Zealand First's nine seats gave it the balance of power between the National Party and the Labour–Green bloc. On 19 October 2017, New Zealand First leader Winston Peters announced that the party was intending to form a minority coalition government with the Labour Party of 55 seats, with confidence and supply agreement from the Green Party. This is the first Government in New Zealand under MMP where the most popular party is not part of the Government. The election resulted in Ardern becoming New Zealand's third female prime minister, and Peters being reappointed deputy prime minister, a role he had first held in 1996–98. This marked an end to nine years under the Fifth National Government, and the beginning of the Sixth Labour Government of New Zealand.