County Carlow was a parliamentary constituency in Ireland, which from 1801 to 1885 returned two Members of Parliament (MPs) to the House of Commons of the United Kingdom, and one MP from 1885 to 1922.

County Carlow had been represented by two seats in the Irish House of Commons.

Under the Acts of Union 1800, it continued to be represented by two MPs, now in the United Kingdom House of Commons.

[3] Therefore, following a dissolution on 26 October 1922, no vote was held in Carlow–Kilkenny at the 1922 United Kingdom general election on 15 November 1922.

The Irish Free State left the United Kingdom on 6 December 1922. Notable MPs for County Carlow included Nicholas Aylward Vigors, a zoologist, John Ball, a naturalist and Under-Secretary of State for the Colonies, Arthur MacMurrough Kavanagh, and James Patrick Mahon.