Montanoa tomentosa was first described by Cervantes in La Llave & Lexarza in 1825. This became Montanoa tomentosa subsp. tomentosa when V. A. Funk revised the classification of Montanoa in her 1982 publication. At the same time, she reclassified M. microcephala as M. tomentosa subsp. microcephala and combined M. rosei and M. gentryi into M. tomentosa subsp. rosei. She was also able to combine several other species of Montanoa into one subspecies, M. tomentosa subsp. xanthiifolia. This new classification scheme was revealed by studying the correlation between the variation in leaves and moisture regimes.