"Delighted to sign for another three years,” Ringrose said.
“It is an exciting time to be involved with Leinster and Ireland. Both squads have ambition to be competing for silverware every year and I’m motivated to do whatever I can to contribute.”
IRFU high performance director, David Nucifora commented: "Garry has had a tough road with injuries since the World Cup in Japan but he is a top international player who delivers big performances for Ireland and Leinster.
“He will be an influential figure at both national and provincial level over the coming years.”