The school children were all in the 14-16 years age group.
The vehicle was carrying students of Sangawade Secondary School of Kolhapur to Tuljapur Temple in Osmanabad district.
Ten children injured in the accident are under treatment at the nearby Ashwini Hospital. The condition of six of them is reported to be critical.
The accident took place around 8 a.m. when the bus was negotiating a sharp turn near the Nagoba Temple, around 15 km from the famous pilgrim centre of Tuljapur, and about 440 km from the state capital.
A speeding private tourist bus was coming from the opposite direction and the two buses collided head-on at the sharp turn, an official at the Osmanabad Police Control Room, said.
The victims were: School bus driver Pratap Surve and students Pankaj Kumbhar, Akshay Patil, Suraj Patil, Vallabh Kambhe, Ganesh Kumbhar and Akash Shirke.