Normanby by Spital, in the Aslacoe Wapentake of Lincolnshire, takes its name from the Old English ethnonym Norðman ‘Northman, Norwegian’ and the Old Norse element bý ‘a farmstead, a village’. A Domesday form of the name, Normanestouu, has as the second element Old English stow ‘a place, a place of assembly’, but this form is not supported by later recordings. The suffix Spital is for its proximity to Spittal in the Street, ‘hospital on a Roman road (Ermine Street)’.

Traditionally, the place-name has been interpreted as referring to a settlement of Norwegians (in an area where most of the Scandinavian settlers were Danes). However, the exact implications of such a name are not yet fully understood and are the subject of ongoing work by Dr Jayne Carroll of the Institute for Name-Studies, University of Nottingham.

There are other Normanbys in Lincolnshire, Normanby in Burton upon Stather and Normanby by Stow.