RCMP say the unidentified girl died Tuesday night, a few hours after a crash on the Gulf Island, northeast of Victoria.
The children were in the rear seat of a Volkswagen Jetta that collided with a GMC van.
The Jetta and van were travelling in opposite directions, but somehow the rear of the Jetta was the most severely damaged section of either vehicle.
A 43-year-old man driving the van was not seriously hurt.
RCMP Sgt. George Jenkins said dozens of rescue and medical personnel were on the scene.
"This is a very difficult time for those directly affected, and the entire community of Salt Spring Island," he said. "We will continue to investigate the cause of this crash and remain committed to supporting the families involved in the difficult times ahead."
An RCMP traffic analyst worked overnight to determine what may have caused the crash and if weather conditions could have played a part.
Police are asking anyone who witnessed the crash at about 2:30 p.m. Tuesday to contact them. (The Canadian Press, CFAX)
Also on HuffPost