Phylum Ascomycota Caval.-Sm. (1998) - sac fungi
   Subphylum Saccharomycotina O.E. Erikss. & Winka (1997) - budding yeasts
     Class Saccharomycetes G.Winter (1880)
       Order Saccharomycetales Luerss. (1877)
         Family Saccharomycetaceae G.Winter (1881)
           Genus Kluyveromyces Van der Walt (1956), nom. cons.