Eupatorieae is one of 43 tribes circumscribed in Asteraceae and it is characterized mainly by opposite leaves, discoid heads, tubular, white, pink, or lilac florets, style branches linear to clavate, and cypsela walls with black or carbonized resin-like deposits in mature stages. The tribe is essentially Neotropical, found in Mexico, Central America, and South America, with 29 genera, of which Trichogonia is one of them. Trichogonia is found only in South America and is characterized by stems with prominent longitudinal ridges and the presence of dense pubescence on the upper throat and lobes of the corolla. The present work is a taxonomic revision of Trichogonia with illustrations and geographic distribution maps for every species. Morphological data were obtained from the field and from specimens from 26 herbaria. From a total of 20 recognized species, 17 occur in Brazil, one is endemic to Bolivia (T. capitata), and two are endemic to Paraguay (T. chodatii and T. phlebodes). From the species currently known to occur in Brazil, 14 are endemic, while T. salviifolia Gardner and T. arguta have widespread distributions. Narrow endemics are found in the states of Bahia (T. harleyi, T. spathulifolia, T. tombadorensis) and Minas Gerais (T. hirtiflora). Other species share a distribution between Pernambuco and Bahia (T. heringeri), Tocantins, Piauí and Bahia (T. campestris), Bahia and Goiás (T. cinerea and T. laxa), Bahia and Minas Gerais (T. villosa), Goiás and Minas Gerais (T. grazielae). Trichogonia occur mostly in savannas cerrados, caatingas, campos gerais, and campos rupestres. Thirteen lectotypifications are designated and 14 new synonyms are proposed in this paper.