Another woman is being treated in hospital for her injuries following the blaze on Saturday at roughly 7.45pm.
Irish police said the house on Castleview Park had been declared a crime scene.
A Garda spokesperson said on Sunday morning that they could confirm two people had died as a result of the fire.
“A female, aged 60 years, and a young boy were fatally injured,” they said.
“A second female, aged in her 50s, is receiving treatment for serious injuries at a hospital in the Midlands.
Gardai in Tullamore are appealing for witnesses to come forward.
