The Old Harry Rocks are chalk formations, on the Isle of Purbeck in Dorset, southern England. They mark the most eastern point of the Jurassic Coast, a UNESCO World Heritage Site.

The chalk of Old Harry Rocks used to be part of a long stretch of chalk between Purbeck and the Isle of Wight. As time passed it suffered erosion from ocean waves, which formed caves and then arches, until it became completely detached from land.

One of these stacks is known as Old Harry. Old Harry's Wife was another stack which was eroded through corrosion and abrasion, until the bottom was so weak the top fell away, leaving a stump.

Old Harry Rocks lie directly east of Studland, about 2.5 miles (4 km) north east of Swanage, and about 5 miles (8 km) south of the large towns of Poole and Bournemouth. To the south are the chalk cliffs of Ballard Down, much of which is owned by the National Trust. The rocks can be viewed from the Dorset section of the South West Coast Path.