Patricia Brown, 52, was a passenger in a car that collided head on with another vehicle on the B769 near Stewarton in East Ayrshire on Sunday evening.
Ms Brown, from Stewarton, was in a Peugeot 206 being driven by a 64-year-old man who survived the crash.
Two 18-year-old men were travelling southbound in a Vauxhall Corsa when they collided with the northbound Peugeot 206 at around 6.30pm.
The driver of a Fiat 500 travelling behind the Corsa swerved to avoid the crash and overturned.
The passenger in the Corsa is in a critical condition at Crosshouse Hospital in Kilmarnock with head and shoulder injuries. The driver suffered shoulder and arm injuries and was said to be in a stable condition.
The 18-year-old Fiat driver escaped with an arm injury.
A Police Scotland spokesman said: "Inquiries are continuing into the cause of the crash and Inspector Drew Robertson of the road policing department at Irvine is appealing for any witnesses to the crash, or anyone with information that may assist his inquiries, to contact Police Scotland on 101."