Eoviscaccia is an extinct genus of chinchillid rodent that lived during the Early Oligocene (Tinguirirican) to the Early Miocene (Colhuehuapian) in what is now South America.

[7] Eoviscaccia was first described by María Guiomar Vucetich in 1989 based on remains found in the Salla Formation of Bolivia and the Sarmiento Formation of Chubut Province, Argentina, with the proposed type species being Eoviscaccia boliviana.

[6] Two other species, E. australis and E. frassinettii, were both named in 1989 and 2012 respectively, with E. australis being found in Chubut, Entre Ríos, Neuquén, and Río Negro Provinces of Argentina, while E. frassinettii was found in the Abanico Formation of Chile.

[7] The following cladogram of the Caviomorpha is based on Busker et al. 2020, showing the position of Eoviscaccia.

[8] Bugtimys zafarullahi Phiomys andrewsi Metaphiomys schaubi Prospaniomys priscus Myocastor coypus Proechimys polioplus Eumysops laeviplicatus Kannabaetomys amblyonyx Echimys chrysurus Ctenomys australis Plataeomys brevis Pithanotomys columnaris Octomys mimax Octodontomys gliroides Chasichimys bonaerense Chasicomys octodontiforme Acarechimys leucotheae Acarechimys minutus Acaremys murinus Galileomys antelucanus Galileomys baios Steiromys detentus Eosteiromys homogenidens Dasyprocta azarae Eoviscaccia frassinettii Eoviscaccia boliviana Garridomys curunuquem Incamys bolivianus Asteromys bolivianus Asteromys punctus Cephalomys ceciae Cephalomyopsis hypselodontus Litodontomys chubutensis Cephalomys arcidens Scotamys antiquus Perimys intermedius Lagostomus maximus Lagidium viscacia Chinchilla chinchilla Banderomys leanzai Soriamys ganganensis Soriamys gaimanensis Luantus propheticus Guiomys unica Microcavia australis Cavia aperea Galea musteloides Dolichotis patagonum