Jack Chambers (born 1990) is an Irish Fianna Fáil politician and Minister for Public Expenditure, Infrastructure, Public Service Reform and Digitalisation since January 2025. He previously served as Minister for Finance from 2024 to 2025, a Minister of State attending cabinet from July 2020 to June 2024, and served as Government Chief Whip from July 2020 to December 2022. He has been Deputy leader of Fianna Fáil since 2024. He has been a Teachta Dála (TD) for the Dublin West constituency since the 2016 general election.

Chambers was born in Galway in 1990 but has lived in Dublin since early childhood. He resides in the Castleknock area of west Dublin. His father, Frank Chambers, from Newport, County Mayo, is a consultant at the Mater Private Hospital, and as chair of Fianna Fáil's Dublin West constituency party was a political ally of Brian Lenihan Jnr. His mother, Barbara Farragher, is from Hollymount, County Mayo. He is not related to the former senator Lisa Chambers, though both have family roots in Newport. He attended Belvedere College and earned a Law and Political Science degree from Trinity College Dublin, before enrolling in medicine at the RCSI, graduating in 2020 after interrupting his studies early in his political career.

Chambers is a member of Dublin GAA club St Brigid's. In January 2024, he came out as gay. In an Instagram post Chambers said: "I am starting 2024 by telling you all that I am proud to say that I am gay. As a politician and citizen, I want to share this today as part of who I am."

In 2014, Chambers reopened the constituency office which had been closed after the death of Brian Lenihan in 2011. He was elected to Fingal County Council in the 2014 local elections, topping the poll in the Castleknock local electoral area. He was deputy mayor of Fingal from 2015 until vacating his council seat on election to the Dáil in February 2016.

In March 2018, Micheál Martin appointed Chambers as spokesperson for Defence. At the 2020 general election, he was re-elected as a TD for Dublin West.

When Martin became Taoiseach, he nominated Chambers as Minister of State at the Department of Finance on 1 July 2020. A fortnight later, after Barry Cowen was sacked as Minister for Agriculture, Food and the Marine, Martin promoted Dara Calleary to replace Cowen, with Chambers succeeding Calleary as Government Chief Whip and Minister of State for Sport and the Gaeltacht. Chambers said he would take an "intensive Irish language course" to prepare for the latter responsibility, as he did not speak Irish fluently at the time. On 17 November 2020, Chambers was appointed to the additional post of Minister of State at the Department of Defence.

In December 2022, after Leo Varadkar became Taoiseach, Chambers was reassigned as Minister of State at the Department of Transport with special responsibility for International and Road Transport and Logistics and Minister of State at the Department of the Environment, Climate and Communications with special responsibility for Postal Policy.

In June 2023, Chambers was appointed as Fianna Fáil's director of local elections for the 2024 local elections.