Emergency services were called around 10-30pm following the crash at the junction of Manchester Road and Lomeshaye Road in Nelson.
A VW Golf travelling along Manchester Road drove through the junction before colliding with a VW Tiguan, which had entered the junction from the nearside, and a Kia Rio which was stationary at a red traffic light on the southbound carriageway of Manchester Road.
Four men from the Golf, aged between 17 and 20, suffered serious injuries and were taken to hospital.
Three people from the VW Tiguan and two people from the Kia suffered minor injuries.
Two men aged 17 and 18 from Nelson have been arrested on suspicion of causing serious injury by dangerous driving.
Sgt Michael Higginson said: “This was a really serious collision which resulted in some significant injuries.
Anyone who has CCTV, dashcam, or phone footage should contact police on 101 quoting log 1502.