Dublin Rathdown is a parliamentary constituency represented in Dáil Éireann, the lower house of the Irish parliament or Oireachtas, since the 2016 general election.

The constituency elects four deputies (Teachtaí Dála, commonly known as TDs) on the system of proportional representation by means of the single transferable vote (PR-STV).

It was established by the Electoral (Amendment) (Dáil Constituencies) Act 2013 and first used at the 2016 election.

[1] It largely replaced the old constituency of Dublin South, with the electoral divisions in Dún Laoghaire–Rathdown of Cabinteely-Loughlinstown, Foxrock-Carrickmines, Foxrock-Torquay and Stillorgan-Leopardstown being transferred to the Dún Laoghaire constituency; and the electoral divisions in South Dublin of Ballyboden, Edmondstown, Firhouse-Ballycullen, Firhouse-Knocklyon, Rathfarnham-Ballyroan, Rathfarnham-Butterfield, Rathfarnham-Hermitage, Rathfarnham-St. Enda's, Rathfarnham Village being transferred to the Dublin South-West constituency.

[2] The Constituency Review Report 2023 of the Electoral Commission recommended that at the next general election Dublin Rathdown be increased to a four-seat constituency with the transfer of territory from Dún Laoghaire.