Kelby is a hamlet in the North Kesteven district of Lincolnshire, England. It lies 5 miles (8 km) south-west from Sleaford, 9 miles (14 km) north-east from Grantham and 3 miles (5 km) south-east from Ancaster. The hamlet forms part of the civil parish of Culverthorpe and Kelby.
Kelby church is dedicated to St Andrew and was previously a chapelry of Heydour ecclesiastical parish. Its tower was rebuilt in 1881 after a collapse. The church basement is Norman and the font Early English, with pews originally from the chapel at nearby Grade II listed Culverthorpe Hall.