Windsor Great Park is a Royal Park of 2,020 hectares, including a deer park, to the south of the town of Windsor on the border of Berkshire and Surrey in England. It is adjacent to the private 265 hectares Home Park, which is nearer the castle. The park was, for many centuries, the private hunting ground of Windsor Castle and dates primarily from the mid-13th century. Historically the park covered an area many times the current size known as Windsor Forest, Windsor Royal Park or its current name. The park is managed and funded by the Crown Estate, and is the only royal park not managed by The Royal Parks. Most parts of the park are open to the public, free of charge, from dawn to dusk, although there is a charge to enter Savill Garden.

In medieval and Early Modern England, Wales and Ireland, a deer park was an enclosed area containing deer. It was bounded by a ditch and bank with a wooden park pale on top of the bank, or by a stone or brick wall. The ditch was on the inside increasing the effective height. Some parks had deer "leaps", where there was an external ramp and the inner ditch was constructed on a grander scale, thus allowing deer to enter the park but preventing them from leaving.