The collision happened at about 17:15 on Thursday on the A803 Blackness Road at its junction with the M9 motorway in Linlithgow.
The crash involved three cars - a grey Vauxhall, a pink Kia and a black Vauxhall.
The female passenger from one of the Vauxhalls, who was in her 70s, was taken to Forth Valley Hospital. She died later. No-one else was injured.
Sgt Roger Park, of Police Scotland, said: "This collision happened during the busy rush hour and I would appeal to anyone who was travelling on the A803 and either witnessed the incident or saw any of the vehicles beforehand to contact police on 101."
A woman has died following a three car crash in West Lothian.