Thecospondylus (THEEK-o-SPON-di-lus, "sheath vertebra") is a dubious genus of dinosaur from the Early Cretaceous of England.

Dr. A.C. Horner, an amateur geologist living at Tonbridge, in the nineteenth century acquired a fossil found in the quarry of Southborough.

He sent it to paleontologist Harry Govier Seeley who in 1882 described and named it as the type species Thecospondylus horneri.

[1] The holotype, BMNH R.291, was found in a layer of the Hastings Sand, sandstone dating from the Valanginian - Hauterivian.

It consist of an elongated natural internal cast or endocast of the neural canal of the sacrum, about sixty centimetres long.