Dún Laoghaire-Rathdown County Council has voted to cut the Local Property Tax by 15%.
Councillors voted on a motion put forward by Fine Gael and Labour this afternoon.
Local authorities are able to vary the rate applied by either reducing or increasing it by 15%.
Dún Laoghaire-Rathdown becomes the third local authority nationwide to do so.
Several councillors said the property tax was unfair and that the proposal to reduce the tax was cynical opportunism on behalf of the governing parties.
Deirdre Kingston of Labour, who proposed the motion along with Neale Richmond of Fine Gael, said it was not opportunistic and said the council could afford to reduce rates for people.
The decision follows that of Fingal County Council last night to also reduce the tax by 15%.
A consultation period will follow today's vote before a final decision is taken in September.