It happened around 6:30 a.m. on NC Highway 50/Benson Highway at J.R. Drive just south of Garner.
The state Highway Patrol said 14-year-old Maria Fernandez Jimenez - a 9th grader at Garner Magnet High School - and her 16-year-old brother were heading to the bus stop in front of their house when a car coming from the opposite direction hit the girl.
Authorities said the girl died at the scene. No other injures were reported.
First Sgt. Jeff Gordon, the public information officer for the Highway Patrol, said the amber lights on the school bus were flashing when the accident happened, but the red ones were not because the bus was not at a full stop.
"We have two independent witnesses right now that were behind the bus that basically state that the bus was not completely stopped and that the red lights were not out," he said.
Gordon added that charges will likely not be filed against the driver of the car because the school bus' red lights were not on, the car was not speeding, and it was dark outside. However, he said they are still investigating.
"Anytime you see a school bus, it's bright, it's yellow, it's there for one reason and one reason only and that's to take children on, load and unload," Gordon said. "Sit down with your children, explain that they always need to look both ways several times and don't take for granted that you can cross the roadway just simply because the bus is stopped."
The school bus, number 1351, was headed to Garner Magnet High School. Another bus was called to the scene to take the six other students who were on board to school.
"The Wake County School systems' thoughts and prayers go out to family and friends of the student," a statement sent out by school officials Monday morning read.
Wake County Schools dispatched its Crisis Response team to the school to provide counseling and other assistance as needed.