The boy was one of two teens who were on a bicycle that was in a collision with a car at about 10.50pm on Saturday.
The two injured 16-year-olds were taken to the Mater Hospital following the crash.
One of the boys was transferred to Beaumont Hospital but died this evening from his injuries.
The other boy's injuries are not thought to be life threatening.
The driver of the car was uninjured.
Gardaí in Fitzgibbon Street are investigating the crash and anyone who may have witnessed the collision is asked to contact Fitzgibbon Street Garda Station on 01-6668400.
Meanwhile, two men were killed in separate road accidents in counties Limerick and Kildare last night.
In Kildare, a 33-year-old man was killed in a two-car collision in Maynooth at about 10pm last night.
The driver of the other car was seriously injured and was taken to the Connolly Hospital in Blanchardstown.
The scene of the collision was examined by Garda forensic collision investigators.
In Limerick, a 21-year-old man was killed in a single vehicle crash at Glin on the main Limerick to Tarbert road shortly before 9.30pm.
The driver was pronounced dead at the scene.
A woman was taken to hospital following the accident. Her injuries are not believed to be life-threatening.
Two other passengers sustained minor injuries.
The road was closed for a garda technical examination.
