Welney is a village and civil parish in the Fens of England, and the county of Norfolk. The village is situated immediately to the west of the parallel Old Bedford River, River Delph and New Bedford River, which are here crossed by the A1101 road. The village is some 15 km (9.3 mi) south-west of the town of Downham Market, 30 km (19 mi) south of the town of King's Lynn and 70 km (43 mi) west of the City of Norwich. The county boundary with Cambridgeshire is adjacent, and the city of Cambridge lies 40 km (25 mi) to the south.
It covers an area of 20.73 km2 (8.00 sq mi) and had a population of 528 in 217 households at the 2001 UK census. For the purposes of local government, it falls within the District of King's Lynn and West Norfolk.
Until 1889 Welney was split between Cambridgeshire and Norfolk. It is now entirely in Norfolk.