Among the over 31,000 recognized species within Basidiomycota, approximately 200 are documented as parasites of other fungi, so-called mycoparasites. They exhibit a remarkable diversity in morphological characteristics, host-parasite interaction structures, and phylogenetic affiliations. Mycoparasitism as a trophic strategy in Basidiomycota has received little attention from the mycological community, with most research performed during the last decades of the previous century. These mycoparasites are documented across three subphyla, encompassing 10 different classes, yet a comprehensive understanding of their evolutionary relationships and host-parasite interaction mechanisms remains limited, and much data are scattered in the literature. This chapter aims to systematically outline the various classes of Basidiomycota known to include mycoparasites, elucidating their diversity, host-parasite interface, life cycle, morphology, and systematic classification. To provide a comprehensive overview of current knowledge on basidiomycetous mycoparasitism, we have compiled a catalogue of presumed mycoparasites, detailing available data for each species.