Bord Gáis Energy has has said it is cutting its gas and electricity prices by 15.5% from November.
The utility is also reducing its standing charges by the same amount in its first price cut in over three years.
The company has said dual fuel customers could save up to €631 per year on their estimated annual bill.
The new rates are effective from November 9th for all residential customers, and are in addition to any discounts that current customers have already.
Bord Gáis Energy Managing Director Dave Kirwan said the market is still uncertain.
"We know energy costs have been hugely challenging for customers over the past two years," he said.
"Whilst the energy market remains uncertain and volatile, we are happy to be in the position to pass on these reductions to our customers today," he added.
SSE Airtricity, Electric Ireland Energia and Pinergy have all announced price reductions in recent months.