Toronto police say the grandmother was "swarmed" by the suspects on Friday afternoon, as she was walking along Sheppard Avenue West, near Jane Street.
According to a police news release, the teens took the woman’s personal belongings and put a hand on her face to prevent her from screaming.
At one point, a suspect “took hold” of the grandchild’s neck and unsuccessfully tried to lift the child out of the stroller, police say.
A TTC bus stopped to let off passengers, at which point the suspects fled.
Anyone with information about the suspects is asked to contact investigators at 416-808-3100, or to call Crime Stoppers at 416-222-8477.