Sedgemoor is a low-lying area of land in Somerset, England. It lies close to sea level south of the Polden Hills, historically largely marsh. The eastern part is known as King's Sedgemoor, and the western part West Sedgemoor. Sedgemoor is part of the area now known as the Somerset Levels and Moors. Historically the area was known as the site of the Battle of Sedgemoor.
Sedgemoor has given its name to a local government district formed on 1 April 1974, under the Local Government Act 1972, by a merger of the municipal borough of Bridgwater, the Burnham-on-Sea urban district, Bridgwater Rural District and part of Axbridge Rural District. The district covers a larger area than the historical Sedgemoor, extending north of the Polden Hills across the Somerset Levels and Moors to the Mendip Hills.