The liverwort Archilejeunea nebeliana Gradst. et Schäf.-Verw. sp. nov. (Lejeuneaceae) is described from submontane rain forest of southern Ecuador. The new species is a member of A. subg. Archilejeunea and differs from all other species of this group by narrowly and obtusely pointed leaves, thin-walled lobule cells, stem epidermis with darker-colored middle lamella, and narrowly elongate female bracts and bracteoles with acute to acuminate apices. The new species constitutes the first record of subg. Archilejeunea from the Andes and is a further addition to the unusually rich flora of the Andes of southern Ecuador. The species is named in honor of Dr. Martin Nebel.