SSE Airtricity is raising its household electricity prices by 5.6% from the beginning of November.
The company said the increase is due to "recently announced increases in regulated networks charges combined with an extended period of rising wholesale energy costs".
As a result of the price change, a typical household customer will pay around €0.90 more per week for their electricity.
It will impact 295,346 household electricity customers in Ireland.
However, the increase will not be applied to SSE Airtricity's "most-in-need" customers using pay-as-you-go meters to manage outstanding debt repayments.
The company’s Director of Home Energy David Manning said the decision was "not taken lightly and is driven by rising costs outside of our control".
He added: "We've sought to insulate our customers from these rises for as long as possible, however regrettably at this time we have no option but to increase our prices."