Knut Arild Hareide (født 23. november 1972 i Bømlo i Hordaland) er en norsk politiker (KrF). Han har vært leder i Kristelig Folkeparti siden 2011 og innvalgt på Stortinget fra Akershus siden 2009. Hareide var Norges miljøvernminister 2004–2005.
Knut Arild Hareide begynte sin politiske karriere som kommunestyrerepresentant i hjemkommunen Bømlo der han ble valgt inn som 18-åring i 1991 (fylte 19 senere samme år). Han var medlem av kommunestyret og kulturstyret på Bømlo i én periode frem til 1995. I 1998 ble Hareide hentet inn av statsråd Jon Lilletun som politisk rådgiver i Kirke-, utdannings- og forskningsdepartementet i Kjell Magne Bondeviks første regjering, sentrumsregjeringen. KrFU fra 1999 til 2001. I 2001 ble han valgt til medlem av sentralstyret i KrF.
Han var også medlem av sentralstyret i KrFs ungdomsparti
Da Kjell Magne Bondevik dannet sin andre regjering, samarbeidsregjeringen, i oktober 2001, ble Hareide utnevnt til statssekretær i Finansdepartementet under statsråd Per Kristian Foss (H). Hareide ble i løpet av perioden som statssekretær også valgt til andre nestleder i KrF på landsmøtet i 2003. Den 18. juni 2004 ble Hareide utnevnt til statsråd og sjef for Miljøverndepartementet (miljøvernminister). Da Hareide tiltrådte som miljøvernminister, bare 31 år gammel, ble han KrFs yngste minister noensinne. Han gikk av som statsråd sammen med resten av regjeringen 17. oktober 2005 etter at SV, Ap og Sp vant valget og Jens Stoltenberg (Ap) kunne danne sin andre regjering.
Hareide var andre nestleder i KrF frem til 2007 da han gikk av etter eget ønske. Den anledningen kom da han før stortingsvalget i 2009 ble nominert på førsteplass for KrF i Akershus. 10.
november 2010 offentliggjorde han at han ønsket å bli ny leder i KrF etter Dagfinn Høybråten, og han ble valgt ved akklamasjon på partiets landsmøte i april 2011. Hareide er på Stortinget leder av Transport- og kommunikasjonskomitéen, og han var også leder av Stortingets 22. juli-komité.
Knut Arild Hareide (born 23 November 1972) a Norwegian politician who serves as a member of parliament from Akershus and as the current leader of the Christian Democratic Party. Hareide served as Minister of the Environment from 2004 to 2005 in the second Bondevik cabinet. In 2007 he announced he would step down from the national political scene for the time being, but he returned when he was nominated as the top candidate for the Christian Democratic Party ticket in Akershus in the 2009 election where he won the county's leveling seat. After Dagfinn Høybråten stepped down as party leader, Hareide was unanimously elected to take his place at the 2011 party convention.
Before his tenure as government minister, Hareide had sat through one term in the municipal council of his native Bømlo, served as a deputy representative to the national parliament as well as working two years as a State Secretary. He was also second deputy leader of his party from 2003 to 2007, having come through the ranks of the party's youth organization.
Outside of politics, Hareide is an economist by education, and he has worked for the media conglomerate Schibsted.
Hareide was active in the Youth of the Christian People's Party, being a member of the national board 1999–2001 before joining the national board of the Christian Democratic Party. He worked as a political advisor in the Ministry of Church Affairs, Education and Research from 1998 to 2000, during the first cabinet Bondevik. He later became State Secretary in the Ministry of Finance from 2001 to 2003 during the second cabinet Bondevik. In 2003 he became second deputy leader of the Christian Democratic Party nationwide.
Prior to the 2009 election, Hareide announced that he would leave national politics if he failed to win a parliament seat.
Although the Christian Democrats suffered nationwide setbacks in 2009, Hareide managed to win Akershus' levelling seat after a close race against Dagfinn Sundsbø of the Centre Party. In parliament, Hareide became the chair of the Standing Committee on Transport and Communications. After Høybråten announced that he would not seek reelection as party leader of KrF, Hareide quickly emerged as the leading candidate to succeed Høybråten, after the two other apparent candidates, Dagrun Eriksen and Hans Olav Syversen, announced they would not run. Hareide is considered to belong to the socially liberal wing of the party, and conservative members of the party have demanded that at least one of the deputy leaders be from the party's conservative wing if they are to support Hareide. Hareide supported the efforts to eliminate the rule which requires Christian Democratic party representatives to declare a Christian faith, and a vote gave a clear majority to abolish that rule two years later. Hareide was unanimously voted in as new party leader at the 2011 convention on 30 April 2011. Hareide declined the nomination as parliamentary leader, and Hans Olav Syversen was elected to this position.
On November 18, 2011, Hareide was appointed to lead the parliamentary committee that is investigating the 2011 Norway Attacks. His nomination to that position was proposed by the red-green parties. On January 23, 2012, Hareide denounced a speech at KrF's local chapter in Sarpsborg that had suggested that the terrorist attacks and the Alexander Kielland disaster were divine warnings or punishments for Norway's policy towards Israel; Hareide said that this was far beyond normal thinking and completely out of line with the party's values.
Hareide comes from a middle class background, his father being a transportation manager and his mother a consultant. Although reluctant to comment on the issue, Hareide was likely single during his first tenure in national politics. He has been confronted with rumours of homosexuality by segments of the media, but these have been dismissed. In 2008 he was reported as having a relationship with Solveig Engevik from Kolbotn, which ended in 2010. In the spring of 2011 he was confirmed in a relationship with school teacher Lisa Marie Larsen.