Eight new species of Mandevilla Lindley are described and illustrated. The new species, six of them rare and endemic, occur in eastern Brazil. Three of the new species (M. fistulosa, M. grazielae, and M. harleyi) are shrubs growing on the upper slopes of granitic inselbergs in Minas Gerais and Espírito Santo in southeastern Brazil. Two species, M. semirii and M. rubra, are woody lianas growing on rock outcrops of quartzite in campo rupestre vegetation of Minas Gerais. Mandevilla hatschbachii, a distinctive shrub known only from three collections, occurs in the campo rupestre formations in eastern Brazil in Bahia. Mandevilla guanabarica, a suffrutescent liana generally misidentified as M. funiformis (Vellozo) K. Schumman, is found at the borders of the Atlantic rainforest in Espírito Santo and Rio de Janeiro. Mandevilla dardanoi is a small shrub endemic to Maciço da Borborema, in northeastern Brazil.