Catherine Murphy is an Irish Social Democrats politician who has been a Teachta Dála (TD) for the Kildare North constituency since the 2011 general election, and previously from 2005 to 2007. She previously served as founding joint Leader of the Social Democrats from 2015 to 2023. In February 2023, she announced that she would stand down as co-leader of the Social Democrats.

The Social Democrats are a centre-left, social-democratic political party in Ireland. Led by Holly Cairns, the party was launched on 15 July 2015 by three independent TDs, Catherine Murphy, and Róisín Shortall, and Stephen Donnelly. It promotes the Nordic model and pro-European views.