Piper is a large genus in the Piperaceae family, with the subgenus Ottonia having about 30 species distributed in the Neotropics, most of which occur in Brazil (26 species). Ottonia is characterized by the flower densely papillate, pedicellate or sessile, with four stigmas, four stamens and 4-ribbed fruits with persistent stigmas. The recent global studies of Piper propose that all the species of Ottonia should be considered a subgenus of Piper. Beacause Brazil doesn't have a revisionary study with the subgenus or with Piper, most of the names of the Piper subgenus Ottonia, about 100 names, need to be re-evaluated. We presented 26 species of Piper subgenus Ottonia, which one three are new species from Brazil Piper brumadinense M. Carv.-Silva & E.F. Guim., Piper cariacicaense M. Carv.-Silva & E.F. Guim., and Piper moringanum E.F. Guim. & M. Carv.-Silva. A synopsis of the Piper L. subgenus Ottonia Spreng.(Piperaceae) is presented, including diagnostics aspects and comments on species, descriptions of the new species, synonyms, lectotypes, and a key to the species and illustrations.