Coordinates: 50°43′30″N 2°56′24″W / 50.725°N 2.940°W / 50.725; -2.940

Lyme Regis ( /ˌlaɪmˈriːdʒɪs/) is a coastal town in West Dorset, England, situated 25 miles west of Dorchester and 25 miles (40 km) east of Exeter. The town lies in Lyme Bay, on the English Channel coast at the Dorset–Devon border. It is nicknamed "The Pearl of Dorset." The town is noted for the fossils found in the cliffs and beaches, which are part of the Heritage Coast—known commercially as the Jurassic Coast—a World Heritage Site. The harbour wall, "The Cobb", features in Jane Austen's novel Persuasion, and in the film and novel, The French Lieutenant's Woman, by local writer John Fowles.

The town was home to Admiral Sir George Somers, its one time mayor and parliamentarian, who founded the Somers Isles, better known as Bermuda.

The town's population at the most recent census was 4,406, 45% of whom were retired.

Lyme is mentioned in the Domesday Book of 1086. In the 13th century it developed into one of the major British ports. A Royal Charter was granted by King Edward I in 1284, with the addition of 'Regis' to the town's name. This charter was confirmed by Elizabeth I in 1591.