During the past two decades, the rift valley system of eastern Africa has been the focus of many interdisciplinary scientific studies because of the peculiar tectonic setting which it represents and the abundant evidence of early man enclosed by rift valley sediments. Geologic studies have largely been confined to individual basins where detailed stratigraphic and sedimentologic investigations have led to the identification of paleoenvironments and paleogeographic reconstructions important to the better understanding of rift valley processes and sedimentation. Through integration of many of these investigations, unifying aspects of tectonic and sedimentary phenomena allow a generalized rift valley depositional model to be developed consisting of six major lithofacies and corresponding depositional environments. These are the 1) interbedded conglomerate and pebbly mudstone facies (alluvial fan); 2) lenticular conglomerate and sandstone facies (fluvial channel); 3) interbedded sandstone, siltstone, tuff and claystone facies (floodplain); 4) lenticular fine-grained sandstone and lenticular-bedded siltstone facies (distributary channel and interdistributary flood basin); 5) arenaceous bioclastic carbonate facies (littoral-lacustrine beach and lagoon); and 6) laminated siltstone facies (shallow-shelf lacustrine and prodelta). The facies of this model interfinger complexly and attain variable thicknesses depending on the individual structural and sedimentological history of each rift valley basin. The association of depositional environments and relationships between basin development and tectonics are unmistakably similar.