The boy was taken from the corner of 45th Avenue and Victoria Street, police said.
Passers-by found him on the ground, beaten, just after 9 a.m. on Garden Crescent in Dorval.
"For now, we're trying to know what happened. Is it related to street gangs? Is it related [to money] or stuff like that? That is what we are trying to know," Montreal police spokesperson Jean-Pierre Brabant said.
He added that investigators are meeting with the victim to find out whether he knows his assailants.
The teen has been released from hospital.