- †Jemezius Beard 1987
- †Uintanius Matthew 1915
Mammalia → Primates → Tarsiiformes → Omomyidae → Omomyinae
- †Uintanius ameghini Wortman, 1904
- †Uintanius rutherfurdi Robinson, 1966
Mammalia → Primates → Tarsiiformes → Omomyidae → Omomyinae → Uintaniini
, Uncia
, Uranomys
, Urocitellus
, Urocyon
, Uroderma
, Urogale
- Uromys (Cyromys) Thomas, 1910
- Uromys (Cyromys) imperator (Thomas, 1888)
- Uromys (Cyromys) porculus Thomas, 1904
- Uromys (Cyromys) rex (Thomas, 1888)
- Uromys (Uromys) Peters, 1867
- Uromys (Uromys) anak Thomas, 1907
- Uromys (Uromys) boeadii Groves and Flannery, 1994
- Uromys (Uromys) caudimaculatus (Krefft, 1867)
- Uromys (Uromys) emmae Groves and Flannery, 1994
- Uromys (Uromys) hadrourus (Winter, 1984)
- Uromys (Uromys) neobritannicus Tate and Archbold, 1935
- Uromys vika Lavery & Judge, 2017 [1]
Mammalia → Rodentia → Muroidea → Muridae
, Uropsilus
, Urotrichus
, Ursidae
, Ursus
- †Uzbekbaatar kizylkumensis Kielan-Jaworowska & Nessov, 1992
- †Uzbekbaatar wardi Averianov 1999
Mammalia → Allotheria → Multituberculata → Cimolodonta