The following lists events that happened during 2018 in New Zealand.

Population
 Estimated population as of 31 December 2018 – 4,886,100
 Increase since 31 December 2017 – 80,700 (1.68%)
 Males per 100 females – 96.8

Incumbents

Regal and vice-regal
Head of State – Elizabeth II
Governor-General – Patsy Reddy

Government
2018 is the first full year of the 52nd Parliament, which first sat on 7 November 2017.

The Sixth Labour Government, elected in 2017, continues.

Speaker of the House – Trevor Mallard
Prime Minister – Jacinda Ardern
Deputy Prime Minister – Winston Peters
Leader of the House – Chris Hipkins
Minister of Finance – Grant Robertson
Minister of Foreign Affairs – Winston Peters

Other party leaders
National – Bill English until 27 February, then Simon Bridges (Leader of the Opposition)
New Zealand First – Winston Peters
Green  –  James Shaw and, from 8 April, Marama Davidson
ACT New Zealand – David Seymour

Judiciary
Chief Justice – Sian Elias

Main centre leaders
Mayor of Auckland – Phil Goff
Mayor of Tauranga – Greg Brownless
Mayor of Hamilton – Andrew King
Mayor of Wellington – Justin Lester
Mayor of Christchurch – Lianne Dalziel
Mayor of Dunedin – Dave Cull

Events

February 

 3 February - Murder of Amber-Rose Rush, a Dunedin teenager. A doctor named Venod Skantha is charged with her murder.

March 

 6 March – The 2018 New Zealand census is held.

May 

 11 May – A wave of about  height, the highest ever recorded, is observed near Campbell Island south of New Zealand; the previous record wave in 2012 was about.
 17 May – The 2018 New Zealand budget is presented to Parlimanet by the Minister of Finance, Grant Robertson.
 19 May – A yellow bow is placed on the Big Lemon & Paeroa bottle to celebrate its 50th birthday.

June 

 4 June – The 2018 Queen's Birthday Honours are announced.
 9 June – The Northcote by-election is won by National, who retain the seat.

August
 15 August – Parliament passes the Overseas Investment Amendment Act 2018, which bans the sale of existing homes to most non-resident foreigners

December 

 1 or 2 December – Murder of Grace Millane, a British tourist. A 26-year-old man is charged with her murder on 8 December.
 31 December – The 2019 New Year Honours are announced.

Sport

Commonwealth Games
 
 New Zealand sends a team of 253 competitors in 17 sports.

Olympic Games

 New Zealand sends a team of 21 competitors in five sports.

Paralympic Games

 New Zealand sends a team of three competitors in two sports.

Sailing
 24 February – 18 March: Auckland is a stopover on the 2017–18 Volvo Ocean Race

Shooting
Ballinger Belt – John Snowden (Ashburton)

Youth Olympics

 New Zealand sends a team of 61 competitors.

Births
 10 November – Asterix, Thoroughbred racehorse

Deaths

January
 4 January
 Owen Hardy, World War II fighter pilot (born 1922)
 Gail McIntosh, politician (born 1955)
 5 January
 Barry Thomas, rugby union player (born 1937)
 Peter Wells, high jumper (born 1929)
 7 January
 Jim Anderton, politician (born 1938)
 Buster Stiggs, musician (born 1954)
 12 January – Richard Peterson, fencer, sports administrator (born 1940)
 17 January – Ted McCoy, architect (born 1925)
 21 January – Michael Selby, geomorphologist (born 1936)
 22 January
 Jack Doms, swimmer (born 1927)
 Kevin Tate, soil chemist, climate scientist (born 1943)
 25 January – Graham Williams, rugby union player (born 1945)
 27 January – Grant Fell, musician (born )
 31 January – Pat Booth, journalist (born 1929)

February
 3 February – Ted Corbett, organic chemist (born 1923)
 8 February – Gary Seear, rugby union player (born 1952)
 10 February – Bevan Congdon, cricketer (born 1938)
 11 February – Darien Boswell, rower (born 1938)
 21 February – Beryl Fletcher, novelist (born 1938)
 25 February – Noel Scott, politician (born 1929)
 27 February – Keith Murdoch, rugby union player (born 1943)

March 
 2 March – Gordon Challis, poet (born 1932)
 9 March – Robin Archer, rugby union player and coach (born 1930)
 11 March – Paddy Donovan, boxer, rugby union player (born 1936)
 14 March
Peter Entwisle, art historian (born 1948)
Mac McCallion, rugby union player and coach (born 1950)
 20 March – Dylan Mika, rugby union player (born 1972)
 28 March – Norm Wilson, cricketer (born 1931)

April
 6 April – Colin McLeod, civil engineer (born 1921)
 10 April – Fergie McCormick, rugby union player (born 1939)
 11 April – Robert Matthews, Paralympic athlete (born 1961)
 16 April – Ivan Mauger, motorcycle speedway rider (born 1939)
 23 April – Haddon Donald, soldier, politician (born 1917)
 24 April – Arthur Eustace, athlete, athletics coach and administrator (born 1926)
 25 April – Margo Buchanan-Oliver, marketing academic (born 1952)
 26 April – David Mitchell, architect (born 1941)

May
 2 May – Katherine O'Regan, politician (born 1946)
 4 May – Tony Steel, rugby union player, politician (born 1941)
 9 May
 Norma, Lady Beattie – vice-regal consort (born 1925)
 Carl Perkins, musician (born )
 15 May – Hopeful Christian, founder of Gloriavale Christian Community (born 1926)
 16 May – Tom Hadfield, rugby league player (born 1934)
 19 May – John Moorfield, Māori language academic (born 1943)
 28 May – Dick Quax, athlete, local-body politician (born 1948)

June
 4 June – J. B. Munro, politician, disability advocate (born 1936)
 7 June – Sir Neil Waters, university administrator (born 1931)
 13 June – Milan Mrkusich, artist, designer (born 1925)
 14 June
 Vincent Gray, chemist, climate change denier (born 1922)
 Steve Kuzmicich, statistician (born 1931)
 18 June – Graham Davy, athlete, sports administrator (born 1936)
 23 June – Koro Wētere, politician (born 1935)
 30 June – Mark Irwin, rugby union player (born 1935)

July
 1 July – Merv Richards, pole vaulter, gymnastics and pole vault coach (born 1930)
 3 July – Gary Bold, physicist (born 1938)
 4 July – Harry M. Miller, impresario (born 1934)
 9 July
 Sam Chisholm, media executive (born 1939)
 Colin Quincey, first person to row solo across the Tasman Sea (born 1945)
 13 July – Naturalism, Thoroughbred racehorse (foaled 1988)
 14 July – Janet Holm, environmental activist, historian (born 1923)
 17 July – David Stevens, screenwriter (born 1940)
 25 July – Rick Littlewood, judoka (born 1940)
 29 July
 Graham Finlay, boxer (born 1936)
 Phillip Orchard, rugby league player (born 1948)

August
 2 August – Bob Berry, dendrologist (born 1916)
 3 August
 Reinhart Langer, botanist, university administrator (born 1921)
 Murray Matthewson, orthopaedic surgeon (born 1944)
 4 August – Delwyn Costello, cricketer (born 1960)
 6 August – Helen Mackenzie, swimmer (born 1930)
 17 August – Warwick Roger, journalist, magazine editor (born 1945)
 18 August – Ronnie Moore, speedway rider (born 1933)
 19 August – Margaret Reid, Presbyterian minister (born 1923)
 20 August – Greg Boyed, television presenter (born 1970)
 21 August – Spencer P. Jones, musician (born 1956)
 23 August – Wendy Hutton, travel and food writer (born 1940)
 30 August – Jack Garrick, ichthyologist (born 1928)

September
 5 September
 Alan Peart,  World War II fighter ace (born 1922)
 John Stacpoole, architect, historian (born 1919)
 7 September – John O'Sullivan, rugby league player (born 1950)
 14 September – Ruth Dowman, athlete (born 1930)
 16 September – Assid Corban, politician, businessman (born 1925)
 22 September – Hayden Poulter, convicted murderer (born 1961)
 24 September – Merv Smith, radio personality (born 1933)

October
 2 October – Barry Linton, cartoonist (born 1947)
 3 October – David Fergusson, psychologist (born 1944)
 4 October
 Penny Bright, activist (born 1954)
 Barrie Frost, psychologist, neuroscientist (born )
 6 October – Wilf Malcolm, mathematician, university administrator