The youngster, aged 12, was hurt in a collision involving a car on the A618 Aughton Road, in Swallownest, close to Aston Academy at around 8.30am today.
Emergency services were called to the scene while worried onlookers made their way to school.
South Yorkshire Police issued a statement.
They said: “We received a report at 8.30am (25 January 25) of a collision on Aughton Road. It is reported a 12-year-old boy was in a collision with a car.
“He was taken to hospital with serious injuries, not thought to be life threatening.”
Yorkshire Ambulance Service also issued a statement.
They said: “We received an emergency call at 8.21am today to reports of a collision between a car and pedestrian on Aughton Road, Swallownest. An ambulance was dispatched to the scene and one patient was conveyed to Rotherham General Hospital.”