Abstract Tectonic inversion has affected the Rukwa, Turkana, and Anza Graben areas to some degree. It is weakest in the Rukwa Rift where anticlines, probably of various origins, provide ambiguous evidence for inversion. In the Turkana area evidence for inversion is strong. It occurs in the youngest rift basins, but seems to have been excluded from the older rift basins. Strengthening and disruption of older faults by igneous intrusions is one possible mechanism for inhibiting inversion on older boundary faults. Inversion in the East African Rift System (EARS) has occurred at least twice, in the Pliocene and Pleistocene, the last phase probably ending in the last 100 thousand years. Inversion features of Paleogene age are very well developed in the southeastern Anza Graben, but decrease in intensity to the northwest The features also show evidence for multiple phases of inversion, that have alternated with extension. In all three areas the inversion episodes developed near the end of rifting. The timing of inversion structures suggests that any driving mechanism must be: of relatively short duration;most effective at the end of rifting; andcapable of alternating with periods of extension. Also, the timing of inversion broadly coincides with periods of extensional activity in the Red Sea-Gulf of Aden. However, the periods of plate motion were much longer than were the episodes of inversion. Consequently, the forces associated with plate motion must be insufficient by themselves to cause inversion, otherwise it would be of longer duration. Perhaps stresses sufficient to cause inversion only arise when regional plate forces are added to local rift-generated forces (such as the gravitational potential of the rift flanks, reduction of buoyancy forces under the rift, and variations in basal shear stress at the base of the crust or lithosphere).