Nobody on the bus was injured.
Trooper Brent Barfield says the wreck happened Tuesday morning on U.S. Highway 84 near Collins.
He says the bus had just picked up students when a 2003 Jeep Cherokee hit the back of it and spun around.
Two passengers in the SUV were not wearing seat belts. They were ejected and killed. Barfield says they were 20-year-old Keannie Love of Hattiesburg and 23-year-old Lishanay Wilks of Prentiss.
He says the SUV driver, 41-year-old Senah Carter of Prentiss, was hospitalized in stable condition.
Covington County Superintendent Clay Anglin says 16 students were transferred to another bus and taken to school.