TDs have stood for a minute's silence in the Dáil in memory of the more than 8,000 men and boys killed by Bosnian Serb forces in the town of Srebrenica in 1995.
The atrocity happened within an area which had been designated by the United Nations to be a "safe haven" and was under the protection of lightly armed Dutch forces.
Tomorrow marks the 30th anniversary of the genocide.
Members of the Bosnia and Herzegovina Association of Ireland were welcomed to the chamber with a round of applause from politicians.
In 2017 Ratko Mladić, who commanded the Bosnian Serb army, was convicted of genocide, crimes against humanity and violations of the laws of war by the International Criminal Tribunal for the Former Yugoslavia.
He remains in jail today.
Speaking in the Dáil, Tánaiste Simon Harris said it was one of the most horrific atrocities to happen on the European continent.
"It is our duty as a country, as a parliament, as an Oireachtas and as an international community to come together and remember the brutality and devastation which occurred," he said.
