Taeniolabis is a genus of extinct mammal from the Paleocene of North America. It is the largest known member of the extinct order Multituberculata, reaching weights of perhaps 30 kg. It is within the suborder of Cimolodonta and is a member of the superfamily Taeniolabidoidea. The genus was named by Cope E.D. in 1882. It is also known as Catopsalis (partly).; Polymastodon (partly) Cope, 1882.

The species Taeniolabis lamberti was named by Simmons N.B. in 1987. It has been found in the Puercan (Paleocene)-age Tullock Formation of Montana. It's not quite as large as T. taoensis, but still a hefty size for a multituberculate.

The species Taeniolabis taoensis was named by Cope E.D. in 1882. It is also known as Catopsalis pollux (Cope, 1882); Polymastodon attenuatus (Cope, 1885); P. latimolis Cope, 1885; P. selenodus Osborn H.F. and Earle C., 1895; P. taoensis (Cope, 1882); T. attetuatus; T. scalper (Cope 1884); T. sulcatus (Cope 1882a); T. triserialis (Granger & Simpson, 1929). They are found in the Puercan-age Nacimiento Formation of New Mexico and Wyoming and in the Ravenscrag Formation of Saskatchewan. This species had a 6 in. (16 cm) long skull. It was a real heavyweight; the largest known multituberculate, this creature was as big as a beaver.