The incident happened on the B9176, known locally as Struie Road, in Fyrish, near Alness, at around 9.35pm on Saturday.
An appeal has been made for witnesses or drivers with dashcams to help police investigate the crash.
A blue Audi RS4 travelling west on the B817 turned right on to the B9176, and Police Scotland said it appears to have lost control and hit a wall at the junction of Fyrish Substation.
Emergency services attended and a 16-year-old male was pronounced dead at the scene.
Sergeant David Miller said: "We are appealing to any other road users who were in the area around the time of the incident to contact us. Did you see a blue Audi? Did you pass it on the road?
"Any small piece of information could be vital in our inquiries.
"In particular, we would ask motorists with dashcams to check their footage as they could have captured an image which could assist us."
A 39-year-old man who was driving the car remains in hospital, along with a 15-year-old girl who was a rear seat passenger. She is in a critical condition.
A 22-year-old woman who was a front-seat passenger was also taken to hospital but has since been released.
An investigation is under way to establish the full circumstances of the incident and the road was closed for several hours as collision investigators examined the scene.