Irish President, Michael D Higgins, offered his condolences to the man’s family.
“As a people, we take great pride in our unbroken record of peacekeeping with the United Nations,” he said.
“However, we must never forget the dangers that come with this work or how the members of our Defence Forces serving on peacekeeping missions abroad risk their lives every day in order to build and maintain peace in conflict zones across the world.”
Irish Defence Minister, Simon Coveney, said it was with profound sadness and a deep sense of shock that he learned of the death.
“At this time I want to express, on behalf of everyone in Ireland, our utmost sorrow at the loss of a young man serving his country and the United Nations overseas,” he said.
“To his family I want to say sorry for their heartbreak and loss.
“To the families of those injured, I want you to know the Defence Forces will do everything to care for and support your loved ones.”
The chief of staff of Óglaigh na hÉireann (the Irish Defence Forces), Lt Gen Seán Clancy, said: “Our thoughts are with his family, his friends and his fellow peacekeepers from the 121st Infantry Battalion.”
He added: “Our focus now is to ensure the safety and continued support for all our personnel deployed in Lebanon.”
The names of the soldiers are not being released at this time but their families have been notified.
Earlier this year, Taoiseach Micheál Martin visited troops serving in Lebanon and laid a wreath to the 47 members of the Defence Forces who had died to date while in service on peacekeeping duty there.