It happened as the boy was playing with friends, just before 7 p.m. on Wednesday, in the 2400 block of North 25th Street.
His mother took him to the hospital to be treated for bite wounds to his back and arms.
He is in stable condition.
In a separate incident, a 6-year-old girl was also bitten in the face by a dog inside a home in Philadelphia's Kensington section.
Police responded to a home in the 2500 block of North Hancock Street around 7 p.m. Wednesday.
Officials say the girl was with her mother at a house with people they know when, for some unknown, reaosn the dog jumped on a bed the child was on and bit her in the face.
She was taken to St. Christopher's Hospital, where she'll be getting stitches to her face.