Magma generation and eruption in continental rift environments has frequently been considered to be a secondary process – simply the result of decompression melting after mechanical thinning. However a new generation of extensional geodynamic models has highlighted the role of magmas in weakening the lithosphere and accommodating strain during the initiation and evolution of continental rifts. Studies of rift magmas therefore provide a way to probe the processes associated with lithospheric thinning, and allow us to assess the possible long term consequences of this thinning on the upper mantle – the future source of mid-ocean ridge magmas. The Main Ethiopian Rift lies at the northern end of the archetypical East African Rift system and provides a 30 million year record of magmatism associated with the Afar plume and continental rifting. Here we present the results of spatial and temporal geochemical studies of rift magmatism in order to constrain the role of magmas in facilitating extension. These data are placed within the existing geodynamic and geophysical framework to provide an integrated model of rift evolution.