Police say it happened around 5:30 p.m. in the 800 block of Mount Royal Avenue.
They say the juvenile had tried to enter another family member's vehicle. He then became angered and used a pipe to break out a window in the vehicle.
Police say while the juvenile was breaking out the window he proceeded to assault a male family member by punching them in the head.
Officers arrested the juvenile and took him to the Cumberland Police Department for processing, and then took him to the Western Maryland Children Center in Washington County, Md.