Gardai at Rathmines are investigating an allegation that a woman was sexually assaulted at Cathal Brugha Barracks.
Military police have also been called in after a woman made a complaint.
The attack is alleged to have happened at 2am this morning.
It's claimed that a woman, who is not a member of the Defence Forces, was brought back to the barracks.
No one has been arrested and the investigation is ongoing.