Police, fire and ambulance services were called to the A403 Severn Road, near Pilning, after a collision between a car and a motorbike at about 8.30am today, Monday morning.
The motorcyclist – a woman in her 20s – sadly died at the scene.
Their next of kin has been informed and a specially-trained officer will be providing them with support.
The car driver was physically unharmed and has been assisting inquiries.
The A403 was closed in both directions to allow collision investigation work to be carried out and the road surface to be checked.
An Avon and Somerset Police spokesperson said: “It is likely to remain shut for the next few hours and therefore we’d continue to ask road users seek an alternative route at this time.
“We appreciate the closure is likely to have an impact on the wider road network and we are grateful for people’s understanding while the emergency services and other agencies continue to respond to this tragic incident.
“Witnesses, or anyone who has relevant dashcam footage showing the vehicles prior to the collision, are asked to call 101 and quote reference number 5225239623 or contact us via our website.”