Lake Kivu displays a peculiar shape for a rift lake, with jagged shorelines associated with flooded river valleys and the presence of a 40×12 km-wide Idjwi Island in the middle of the basin. Based on this shape, the origin of Lake Kivu has been inferred to result from a natural damming of major rivers by the Virunga lavas. However, some geomorphological analyses of the Kivu rift suggest a more complex history. By comparing tectonic and paleotectonic structures with the distribution of volcanism, we provide elements of answers to questions related to the development of this part of the rift and its implications for Lake Kivu. Results indeed suggest that rifting reactivated NE-SW oriented structures probably related to the Precambrian basement, creating transfer zones and influencing the location and distribution of volcanism. Both volcanic provinces, north and south of the Kivu basin, extend into Lake Kivu and are connected to each other with a series of eruptive vents along the western rift escarpment. The complex morphology of this rift basin, characterized by a double synthetic half-graben structure, might result from the combined action of normal faulting, magmatic underplating, volcanism and erosion processes.