Sphenocoelus is an extinct genus of brontothere known from North America and Asia during the Middle Eocene.
Sphenocoelus is an average-sized brontothere, with a dolichocephalic skull. Some specimens of Sphenocoelus bear a prominent sagittal crests, though others lack them entirely. The molars are long and narrow, and the third and fourth premolars have a cusp on the posterior medial (central hind) portion of the tooth. They bear 4 digits on the forefeet.
Sphenocoelus has had a complicated classification history, with many genera being split off or lumped within the group at various times. Currently, Sphenocoelus is placed within Brontotheriidae. The genus Dolichorhinus was once considered a species of Sphenocoelus, S. hyognathus, but is now in its own genus.