Cian O'Callaghan (born 7 May 1979) is an Irish politician who has been a Teachta Dála (TD) for the Dublin Bay North constituency since the 2020 general election.

He graduated with a MA in Politics and a Higher Diploma in Social Policy from University College Dublin (UCD).

[9] O'Callaghan was elected to Fingal County Council on his first attempt in 2009, representing Labour, taking the second seat in the Howth-Malahide local electoral area.

Following the results of the 2011 Irish general election, O'Callaghan fiercely opposed Labour entering into a coalition government with Fine Gael.

[5] During his time as mayor he highlighted the problems faced by homeowners in a number of newer developments in the Fingal area, where building materials contaminated with pyrite caused severe damage.

[10] O'Callaghan contested the 2016 general election for the Social Democrats in Dublin Bay North and received 3,864 first preference votes, being eliminated on the 12th count.

[25] On 1 July 2023, it was announced that O'Callaghan had been appointed to the newly created role of deputy leader of the Social Democrats.