Theddlethorpe comprises two close villages and civil parishes, Theddlethorpe St Helen, and Theddlethorpe All Saints, in the East Lindsey district of the county of Lincolnshire, England. These two villages have operated as one entity for many years. They are situated approximately 3 miles (5 km) north from Mablethorpe and on the coast of the North Sea. The National Grid-owned Theddlethorpe Gas Terminal processes natural gas extracted from beneath the North Sea for use in the UK. Theddlethorpe St Helen has a primary school.