Maasai pastoralists in Kenya are rapidly diversifying. Maasai may now derive their main livelihoods (and sometimes considerable income) from farming, wildlife tourism, and/or the leasing of land for large-scale cereal cultivation. The spread of large-scale commercial cultivation competes with wildlife for grazing land, and wildlife populations around protected areas are rapidly declining as a result. This paper presents new data to analyse the way returns from different land uses, and the social structures affecting their distribution, influence the land-use choices being made by Maasai around the Mara National Reserve in Kenya. Returns to different interest groups from livestock, cultivation, and wildlife enterprises, seen in the light of current social, economic, and political trajectories, can help to clarify likely future land-use trends in the Mara. In particular, community conservation initiatives that seek to make conservation worthwhile to reserve-adjacent dwellers inevitably have a strong economic dimension. However, the choices made by Maasai landowners are not a simple function of the economic returns potentially accruing from a particular enterprise. They are as much or more influenced by who is able to control the different flows of returns from these different types of enterprise. These findings are relevant not only for the wider Serengeti-Mara Ecosystem, but also for pastoral livelihoods and wildlife conservation elsewhere in sub-Saharan Africa.