Old Somerby (pronounced Summerby) is a village and civil parish in the South Kesteven district of Lincolnshire, England, 3 miles (5 km) south-east of Grantham.

Schools, shops and other amenities are available in Grantham (4 miles (6.4 km), to which there are occasional daytime, weekday buses.

[6] Somerby was a colony of the Danes who ruled Lincolnshire after peace was made with King Alfred in 878.

The village is listed in the Domesday Book,[7] where the King's tenant-in-chief is given as Walter of Aincourt.

[10] The Old Rectory in School Lane is Grade II listed and dates from about 1700, with alterations and additions in the late 18th, the 19th and the 20th centuries.