The funeral mass for Conor, Darragh and Carla McGinley will take place later.
The three children were found dead in their home in Newcastle in west Dublin last week.
A Mass of the Angels will take place at 11.00am in Rathcoole for nine-year-old Conor, seven-year-old Darragh and their three-year-old sister Carla.
The bodies of the three children were discovered in their home last Friday night.
Their mother Deirdre Morley has been charged with their murders.
She was remanded in custody earlier this week and is due back in court next Wednesday.
In the aftermath of their deaths, their father Andrew McGinley said 'every breath is a struggle' and he urged all parents to cuddle their children every chance they get and to tell your children you love them.
After this morning's mass in the Church of The Holy Family, Conor, Darragh and Carla will be laid to rest in nearby Newcastle Cemetry.