ACT New Zealand, known simply as ACT (), is a right-wing, classical-liberal political party in New Zealand. According to former party leader Rodney Hide, ACT's values are "individual freedom, personal responsibility, doing the best for our natural environment and for smaller, smarter government in its goals of a prosperous economy, a strong society, and a quality of life that is the envy of the world". Young ACT is its affiliated, albeit unofficial, student wing.

The name is an acronym of Association of Consumers and Taxpayers, which was founded in 1993 by Roger Douglas and Derek Quigley and became a political party for the 1996 election. An associate of Douglas, Richard Prebble served as party leader from 1996 to 2004. Under Prebble's leadership the party held nine seats in Parliament. Rodney Hide served as leader from 2004 to 2011. ACT was briefly led by former National Party leader Don Brash for the 2011 election, after which the party caucus was reduced to one seat.

ACT gave support to the Fifth National Government from 2008 to 2017. It is currently led by David Seymour, who became the party's leader in October 2014 and has been an elected MP of the party since September 2014. During the 2017 election, ACT retained its sole seat in Epsom and received 0.5% of the party vote. Benefiting from the collapse of the National Party vote, ACT won 7.6% of the party vote and 10 seats in the 2020 election, its best result since its founding.