An election to Dublin County Council in the electoral county of Dún Laoghaire–Rathdown within Dublin County took place on 27 June 1991 as part of that year's Irish local elections.

28 councillors were elected from 7 local electoral areas on the system of proportional representation by means of the single transferable vote for a five-year term of office.

[1] It was one of three electoral counties within Dublin County at this election, the others being Fingal and South Dublin.

The councillors elected for the electoral areas of Ballybrack, Blackrock and Dún Laoghaire also served as the members of the Corporation of Dún Laoghaire, the council of the Borough of Dún Laoghaire.

The Borough of Dún Laoghaire was also disestablished as of that date.