Officers were called to the scene of the two-vehicle collision, which involved a Skoda Fabia and a Honda Civic, at around 5pm on the dual carriageway – the A26 between Ballymena and Antrim.
The woman who died was a passenger in the Skoda Fabia.
She has been named as Jean Wilkinson, aged in her 60s.
A passenger in the Honda Civic was treated for her injuries at the scene by ambulance staff and subsequently taken to hospital as a precaution.
The driver and another passenger in the Skoda Fabia were also treated at hospital for what are believed to have been minor injuries.
Inspector Martin Ruddy said: “I’m appealing to anyone who was on the Lisnevenagh Road around the time of the collision and witnessed what occurred to get in touch with us.
“We’re also appealing to anyone who was travelling on the road at the time and may have Dash Cam footage they believe could assist with our investigation to contact police in Ballymena on the non emergency number 101, quoting reference 1004 10/10/17.”