Fosdyke is a village and civil parish in the Borough of Boston, Lincolnshire, England. The population of the civil parish at the 2011 census was 480.
The name derives from the Old English and Old Norse “fotrs dic”, meaning Fotr’s (personal name) ditch.
Fosdyke’s Grade II listed Anglican church is dedicated to All Saints. In 1871–72 the church was entirely rebuilt in brick on the site of an older church, in an Early English style. The architect was Edward Browning.
In 1885 Kelly’s Directory reported the existence of a Primitive Methodist chapel, a coastguard station, and a 100-year-old almshouse, founded by Sir Thomas Middlecott for the Fosdyke and Algarkirk parishes.