A new species of Passiflora from the rocky fields (“campos rupestres”) of Minas Gerais State is described: P. rupestris, which belongs to Passiflrora sect. Decaloba. The species is distinguished by having a 3-lobed obtriangular leaf blade that is longer than wide, of small size (1.5–2.9 × 1.3–2.2 cm), without ocelli, and with slightly divergent lobes (27–40°), and a particular combination of characteristics of the flower and fruit. The species is illustrated and its affinities with other species are discussed. Passiflora rupestris must be regarded as critically endangered because of its extremely limited occurrence.