Weston Big Wood (grid reference ST455750) is a 37.48 hectare woodland west of the town of Portishead, North Somerset, England.

Some of its internal features e.g. old stones, ditches and banks are thought to be medieval boundaries, dating from the Middle Ages and used to divide the wood into sectors.

[1] More recently, after the manor of North Weston was sold to the City of Bristol in 1637,[2] marker stones were placed to mark a boundary across the woodland.

[1] There is a wide coppiced open area inside the wood, created as a butterfly feature as part of the reserve management work, called "The Ride".

[9] An area of 38 hectares is managed as a nature reserve by Avon Wildlife Trust, and purchased with support from the Heritage Lottery Fund, the Countryside Agency, and donations from members and local people.