Caythorpe is a village and civil parish in the South Kesteven district of Lincolnshire, England. The population at 2011 census was 1,374. It is situated on the A607, approximately 3 miles (5 km) south from Leadenham and 9 miles (14 km) north from Grantham. Caythorpe Heath stretches east of the village to Ermine Street and Byards Leap.

South Kesteven is a local government district in Lincolnshire, England, forming part of the traditional Kesteven division of the county. Its council is based in Grantham. The district also includes the towns of Bourne, Market Deeping and Stamford, along with numerous villages and surrounding rural areas.