The accident occurred on Road 107 about 12:30 a.m. near the Neshoba-Newton County line, The Neshoba Democrat reported.
Neshoba County Sheriff Tommy Waddell identified the victims as siblings Dasyanna John, 9; Duane John, 8; Bobby John, 7; Quinton John, 4; and Kekaimeas John, 18 months; and Diane Chickaway, 37.
The children's father, who was driving the car, Dewayne John, was hospitalized, Waddell said.
Two other passengers, the children's mother, Deanna Jim, 28, and Dale Chickaway, 37, were not seriously injured, he said.
All nine belong to the Choctaw Tribe's Pearl River community, the sheriff said.