Patagosmilus ("Patagonian knife" in Greek) is an extinct genus of meat-eating metatherian mammal of the Thylacosmilidae family, that lived in the middle of the Miocene in South America. Like another representatives of this family, like Thylacosmilus atrox and Anachlysictis gracilis, it was characterized by its elongated fangs of the upper jaw, similar to the well known "sabertooth cats" (Machairodontinae), which they were ecological equivalents.