The genus Rhagovelia is revised for the region comprising Borneo, Celebes, and the Moluccas. Redescriptions are given for species previously described from the area, and 26 new species are described. Figures of the dorsal habitus and key characters are provided for all species, accompanied by a key to species and distribution maps. Species occurring in the region are divided into eight monophyletic intrageneric species groups, some of which also contain members outside the region, based primarily on wing venation, thoracic morphology, and genitalia. A zoogeographic analysis is presented based on the distribution of these groups within the Malay Archipelago and surrounding regions. We conclude that the present Rhagovelia fauna of the Malay Archipelago is derived from species which originated in continental Southeast Asia, Australia, and New Caledonia. Distinct lineages have entered the region from each of these three source areas, penetrating the archipelago with differing degrees of success and contributing to the fauna of each individual island to varying extents. Species groups of Asian origin do not extend beyond Celebes and the Lesser Sunda islands, while species groups of Papuan origin are absent in the Lesser Sundas and do not extend west of Borneo. Endemic species groups have also arisen on New Guinea, the Philippines, the north Moluccas, and Borneo. A section on ecology and behavior is provided, dealing in particular with the altitudinal segregation of species on individual islands. The following new Rhagovelia species are described: bacanensis, borneensis, celebensis, christenseni, grayi, hamdjahi, incognita, lorelinduana, meikdelyi, melanopsis, minahasa, obi, pruinosa, ranau, sabela, samardaca, samarinda, sarawakensis, silau, simulata, sondaica, sulawesiana, tawau, lebakang, unica, and wallacei. Rhagovelia mindanaoensis Hungerford and Matsuda 1961 is synonymized with Rhagovelia orientalis Lundblad 1937 (new synonymy)
