The 36 year old woman died after being shot at around 8.40pm in Collins Place, Finglas East in Dublin.
Sandra Boyd was taken to the Mater Hospital after the incident where she was later pronounced dead.
The man in his 20’s who was arrested this morning is currently being held in Finglas Garda Station.
The investigation is on going into whether Sandra Boyd was accidently killed by the gun which had been brought into her home.
The post-mortem is complete and the Gardaí are appealing to anyone who may have witnessed the shooting or may have been in the area of Collins Place between 8pm and 9pm on Saturday evening.
If anyone has any information, they are encouraged to contact FInglas Garda Station.