The shooting occurred early Sunday morning at a house in the Thomond Road area of the West Dublin suburb.
The victim was pronounced dead at the scene after receiving several gunshot wounds.
The state pathologist has been notified.
"The scene is currently preserved and a technical examination is to be carried out by the Garda Technical Bureau," a garda spokesperson said.
Gardaí have asked for anyone with information relevant to the incident to come forward.
If you believe you have information you should contact Ballyfermot Garda Station on 01 666 7200, the Garda Confidential Line on 1800 666 111 or any Garda station.
