The incident occurred on the A61 between Busby Stoop and Carlton Miniott at around 9.25pm on Wednesday 7 March 2018.
It involved a green VW Bora and a black Ford Focus that was heading in the opposite direction towards Thirsk.
Two 17-year-old boys, rear seat passengers in the VW Bora, were sadly pronounced dead at the scene by paramedics.
Another two passengers in the same vehicle, an 18-year-old man and a 17-year-old boy, are in a critical condition at James Cook University Hospital in Middlesbrough and Leeds General infirmary respectively.
The driver of the VW Bora, a 22-year-old man, is receiving treatment at James Cook University Hospital for non-life-threatening injuries.
All the occupants in the VW Bora are from the Thirsk area.
The driver of the Ford Focus, a 27-year-old man from outside the area, was discharged from James Cook University Hospital following treatment. A passenger in the car, a 24-year-old woman, is receiving treatment at the hospital. A three-year-old girl and a six-month old boy have also been kept in hospital for observations as a precaution.
Police have said that they are not yet in a position to confirm the identity of the two boys who died in the collision.
In total, there were seven land ambulances, an air ambulance and coastguard rescue helicopter in attendance at the incident, along with police and fire crews.
The scene remained closed to traffic until 4.45am on Thursday while the police investigated the circumstances of the collision and to allow the vehicles to be safely recovered.
Officers are continuing to appeal for people to come forward to assist the investigation, including witnesses to the actual collision, anyone who recalls seeing any of the vehicles involved prior to the incident, and anyone who may have dash-cam footage that could help with enquiries.
If you can help, please call North Yorkshire Police on 101, select option 2, and ask for the Major Collision Investigation Team or email MCIT@northyorkshire.pnn.police.uk
Please quote reference number 12180039673 when providing details about this incident.