Oxyacodon Osborn and Earle, 1895 is a Puercan anisonchine periptychid most closely related to Conacodon. Valid species of Oxyacodon are O. apiculatus Osborn and Earle, 1895; O. agapetillus (Cope, 1884); O. priscilla Matthew, 1937; O. ferronensis n. sp.; and questionably O. marshater Van Valen, 1978. The upper dentitions of all species except O. marshater are described and figured. These most closely resemble Conacodon entoconus and C. cophater in the lingual expansion of the hypocone and reduction of the P 3 protocone. Fimbrethil ambaronae Van Valen, 1978 is a junior synonym of O. agapetillus. O.tecumsae Van Valen, 1978 is probably a junior synonym of Mixodectes malaris (Cope, 1884). Oxyacodon josephi Van Valen, 1978 does not belong to this genus but could be related to Hemithlaeus. Lessnessina packmani Hooker, 1979 is not an anisonchine and is not closely related to Oxyacodon, but bears some resemblance to anagalidans.--Modified journal abstract.