A bus carrying 45 children, aged between five and 11 from Exford Primary School, collided with a truck at about 3:40pm yesterday near Melton, a suburb about 50km west of Melbourne's CBD.
Emergency services rushed to the scene and found that the bus had overturned and some students managed to get out of it on their own or with the help of passers-by.
A short time later the fire brigade arrived and helped to extricate several other trapped children, with eleven students and one adult being taken to hospital.
The bus driver suffered minor injuries.