A 14-year-old girl was among three members of the same family killed in a crash between a car and a minibus.
The collision happened just after midnight on Sunday on the A34 in Alderley Edge, Cheshire, said police.
A man, aged 47, and the teenager died at the scene. A 41-year-old woman in the same car died later in hospital.
A nine-year-old girl and a 19-year-old woman, who were also in the vehicle, are seriously injured in hospital.
A Cheshire Police spokesman said the nine-year-old girl was in a critical condition and the 19-year-old was in a serious condition.
The spokesman added: "The family are being supported by specialist officers at this difficult time."
A number of casualties from the minibus were treated at the scene and taken to hospital.
Police are appealing for witnesses.