The students from Kinsale Community School in Cork were the overall winners of the BT Young Scientist Exhibition at a ceremony hosted by RTE's Aidan Power and presenter Roisin Ni Thomain.
Third-years Ciara Judge, Emer Hickey and Sophie Healy-Thow took home the top prize.
The girls were presented with a cheque for €5,000, the chance to represent Ireland at the 25th European Union Young Scientist competition in Prague in September and a Waterford crystal trophy.
"I can't believe it," said Emer afterwards.
A total of 550 projects were accepted to take part in the finals, of which 111 were projects entered from schools in Dublin.
Padraig Buggy (15) from Belvedere College was the first Dublin winner on stage, to collect a special award from the Irish Science Teachers Association.
Shane Curran (12), a first-year from Terenure College, won a special award from Google Trailblazer as well as a junior technology award.