Avebury is the site of a large henge and several stone circles in the English county of Wiltshire surrounding the village of Avebury. It is one of the finest and largest Neolithic monuments in Europe dating to around 5000 years ago. It is older than the megalithic stages of Stonehenge, which is located about 32 km to the south, although the two monuments are broadly contemporary overall.

Most of the surviving structure consists of earthworks, known as dykes. The circle encloses an area of 28.5 acres. The only known comparable sites of similar date (Stonehenge and Flagstones) are only a quarter of the size of Avebury.