Worth Forest is a 43.8-hectare (108-acre) biological Site of Special Scientific Interest south of Crawley in West Sussex. It is in the High Weald Area of Outstanding Natural Beauty.

This ancient wood is in a ghyll formed by a stream which has eroded soft sandstone. The poorly drained valley bottom has carpets of Sphagnum while the upper slopes are dry and have a diverse community of mosses, liverworts and lichens.

The site is private land but it is crossed by public footpaths.