Janesah Goheen, of Oak Harbor, died of her injuries 11 days after the collision on State Route 20. She was driving a 1993 Acura.
Her twin, Janeah Goheen, 17, who was a passenger in the back seat of the vehicle, was declared dead at the scene Oct. 31.
Their friend Alysha Pickler, 18, of Oak Harbor, who was riding in the front seat, was injured but is recovering.
Ian Blackstock, 52, of Oak Harbor, was arrested on suspicion of vehicular homicide and vehicular assault.
The Washington State Patrol said Blackstock was driving a 2006 Ford Mustang and his car began to fish-tail on wet pavement as he approached the intersection of SR 20 with Gibraltar Road and crossed into the oncoming lane, striking the Acura driven by Janesah Goheen.