Ancaster is a village and civil parish in the South Kesteven district of Lincolnshire, England, on the site of a Roman town. The population of the civil parish was 1,317 at the 2001 census increasing to 1,647 at the 2011 census. The civil parish includes the settlements of Sudbrook and West Willoughby.
The population declined between the 1991 and 2001 census.