The bus had students from the Government High School, Dharmapura in Hunsur Taluk of Mysuru district.
At least 18 schoolchildren and three teachers were injured when their bus met with an accident in Karnataka's Shivamogga district on Thursday morning, the police said.
The bus, which had 47 students on board, overturned at Vakkodi near Tumari in Sagar Taluk of the district around 9 am.
The bus was reportedly speeding, leading to the accident.
The injured were taken to the hospital.
All children are students of the Government High School, Dharmapura in Hunsur Taluk of Mysuru district.