Recent fieldwork in Gabon yielded material of a previously unknown Impatiens species that resembles Impatiens kamerunensis and I. oumina. Molecular analyses based on ImpDEF1, ImpDEF2 and ITS in combination with a thorough comparative morphological study confirmed the status of the newly collected material. It is phylogenetically positioned within the West-African Impatiens clade. Impatiens nzabiana can be distinguished from I. kamerunensis in having a narrowly lanceolate leaf shape, a 7-7.5 mm long appendage on the lower lateral petal and the presence of 3-8 mm long fimbriae at the leaf base. Molecular data strongly support a sister group relationship with I. amnia, whereas both I. nzabiana and I. oumina are sister to I. kamerunensis. Impatiens oumina is similar to I. nzabiana by the presence of long fimbriae near the base of the leaf and simple or sparsely branched stems, but can be easily distinguished from the new species by the narrowly ovate leaf shape, the smaller size of both the plants and the flowers, the subumbellate racemes, the pinkish-white corollas and the white spur sepals. By calculating age estimates and investigating the biogeography off. nzabiana and its closest relatives, we have been able to hypothesize the evolutionary history of the new species.