Stenopelix (meaning "narrow pelvis") is a genus of probable basal ceratopsian from the Early Cretaceous of Germany.

In 1857, based on this fossil, Christian Erich Hermann von Meyer named the type species Stenopelix valdensis.

The holotype, GZG 741/2 (earlier GPI 741–1, 2), found in the Obernkirchen Sandstein Formation, consists of the impressions of an almost complete skeleton, lacking the skull and the neck.

In 1974 Teresa Maryańska suggested it to be a pachycephalosaur, one of the oldest known, due to the apparent exclusion of the pubis from the acetabulum, and the presence of strong caudal ribs.

But paleontologists Richard J. Butler and Robert M. Sullivan nonetheless view the species as being Marginocephalia incertae sedis, rejecting the presumed synapomorphies with the Pachycephalosauria as incorrect identifications or lacking cogency because of a possible presence in ceratopsian groups.

[6] A cladistic analysis performed by Butler et al. (2011) showed that Stenopelix is a basal member of the Ceratopsia, and its sister taxon is Yinlong.