The 57-year-old victim was rushed to hospital following the collision, which took place this morning (Wednesday) in South Street.
A man who was driving the vehicle has been arrested over the incident.
Emergency services were called to the scene, near the junction with School Brae, just before 8.45am.
The road had been shut at the time for resurfacing work.
A Police Scotland spokesman said: “Police received a report of a woman having been struck by a lorry on South Street in Bo’ness around 8.45am.
“The 57-year-old woman has been taken to the Royal Infirmary of Edinburgh with life-threatening injuries.
"The male driver of the lorry has been arrested in connection with road traffic offences and enquiries are ongoing.”
A Scottish Ambulance Service spokeswoman added: “We dispatched a critical care paramedic, two rapid response vehicles and an ambulance crew to the scene, and a female patient was transported to the Edinburgh Royal Infirmary.”