Presentation College, Ballyphehane were announced as the winners of the All Island School Choir Competition on RTÉ One on Sunday night.
The Co Cork secondary school also won the title in 2010.
In the 2013 Grand Final at the Titanic Centre, Belfast, the Cork students competed against Blackrock College, Dublin; Strathearn School, Belfast and Ursuline College, Sligo.
Watch the Grand Final at: www.rte.ie/player/ie/show/10226360.
After Presentation College's victory, winning Choir Director Anne Dunphy said: "It's been a fantastic experience for the girls in teamwork, commitment and achieving goals. I'd like to thank RTÉ, Co-operation Ireland and especially Tommie Gorman for their dedication in organising the competition.
"Winning the All Island School Choir Competition means so much to not only the girls in the choir, but to the whole school and the wider community."
Executive Producer for RTÉ, Tommie Gorman, said: "For the past five years, this competition has been a celebration of the ethos of teamwork and friendship promoted in school choirs.
"We are proud to be able to broadcast these beautiful musical performances and showcase the talents of young people to hundreds of thousands of viewers throughout the island of Ireland.
"This has been a wonderful night for all the choirs who competed here in Titanic Belfast and also for all the choirs who entered and competed this year."