The child was riding on the school bus and the other two people confirmed dead were in the other vehicle involved in the Seminole County collision, the Oklahoma Highway Patrol said. Their identities have not been released.
Several others were injured. Details on the extent of their injuries and what led to the collision were not released. It was not immediately clear how many children were on the bus.
Authorities have closed a portion of highway US 377 in the town of Bowlegs, located 60 miles east of Oklahoma City, KOCO-TV reported.
Investigators have not confirmed which school the bus was from.