The largely 15th-century church of St Guthlac is the only church in Market Deeping, and is part of the Church of England. The church is in the Diocese of Lincoln in the Deanery of Elloe West. St Guthlac's is a member of the Deepings Churches Together, a local organisation of churches within The Deepings, and a member of the St Guthlac fellowship. As of 2020 the rector is the Reverend Georgina Holding.
Architecture
On the south face of the tower is a limestone sundial inscribed with "The day is thine", with a similar sundial on the north face which bears the words "The Night cometh". The nave is supported on the south aisle by Norman arches, whereas those on the north aisle are later Gothic period. The church organ is Victorian. The stained glass windows in the chancel depict scenes of the life of the St Guthlac, including one in which he is seen sailing through what is now the fens to establish a monastery, now Crowland Abbey.[citation needed]