Alice Mahon (née Bottomley; 28 September 1937 – 25 December 2022) was a British trade unionist and Labour politician who served as Member of Parliament (MP) for Halifax from 1987 until 2005.

Mahon was a left-winger who was a member of the Socialist Campaign Group and was a Eurosceptic, and a frequent rebel against Labour's Blair government. She left the House of Commons in 2005 and resigned from the Labour Party in 2009, expressing objections to the party's political positions and internal operations. However, she rejoined the party in 2015 in support of Jeremy Corbyn's election as leader.

Born Alice Bottomley in Buttershaw, Bradford, she attended grammar school in Halifax and worked in the National Health Service as a nursing auxiliary for ten years. In 1979, she gained a BA in Social Policy from the University of Bradford and taught Trade Union Studies at Bradford College from 1979 to 1987. Meanwhile, she was a councillor on Calderdale Council.

Mahon was first elected for the Halifax constituency at the 1987 general election. In 1994, commenting on Tony Blair, Mahon told Chris Mullin that she was "in the Stop Blair camp" of the party.

Mahon opposed the missile defence plans during her period in the House of Commons and sought to protect benefits for parents, women's rights (particularly regarding abortion), and gay rights. Mahon was also a supporter of reform of the House of Lords. She was opposed to the Iraq War, speaking in 2004 of the "cruel barbarism that has been inflicted upon Iraq". She told the 2003 Labour Party Conference, "we were lied to about WMD and there is no delicate way of putting it".

In a July 2003 Commons debate, she queried the support of John Reid, then the Secretary of State for Health for Foundation Hospitals: "How can the Secretary of State stand there as a Scottish MP who is not going to have one of these divisive hospitals, and yet is voting to inflict them on the people of Halifax?" In a version of Tam Dalyell's West Lothian question, the government in the subsequent parliamentary division would have lost the vote without the support of Scottish and Welsh Labour MPs. Labour's majority of 164 was reduced to 17 because of votes against the motion and abstentions. "As English MPs, we have to settle this question of Scots and Welsh MPs voting for things they're not going to have", Mahon said at the time.

In November 2005, a film documentary by Sigfrido Ranucci of Italy's Rai News 24, The Hidden Massacre, asserted that the US military had used white phosphorus (WP) as an incendiary weapon, including against civilians in the Second Battle of Fallujah. The RAI documentary also quoted a 13 June 2005 UK MOD letter to Mahon, stating that:

The US destroyed its remaining stock of Vietnam era napalm in 2001 but, according to the reports for 1 Marine Expeditionary Force (1 MEF) serving in Iraq in 2003, they used a total of 30 MK 77 weapons in Iraq between 31 March and 2 April 2003, against military targets away from civilian areas. The MK 77 firebomb does not have the same composition as napalm, although it has similar destructive characteristics. The Pentagon has also told us that owing to the limited accuracy of the MK 77, it is not generally used in urban terrain or in areas where civilians are congregated.