All Saints Church is a redundant Anglican church in the village of Theddlethorpe All Saints, Lincolnshire, England. It is recorded in the National Heritage List for England as a designated Grade listed building, and is under the care of the Churches Conservation Trust. The church stands to the east of the A1031 road in the area of the village named Theddlethorpe All Saints, and is some 3 miles (5 km) northeast of Mablethorpe. It has been called the "Cathedral of the Marsh".