This study focuses on public investments and policy reforms for leveraging growth spillovers at the Africa regional level. It reviews first the theory and evidence of knowledge and growth spillovers generally and second the evidence in the African context. Given the limited and scattered evidence of actual past spillovers, it reviews recent ex ante simulations using partial and general equilibrium models to stress the potential for spillovers from greater cooperation in agricultural research, and from trade liberalization, policy harmonization and investments in infrastructure. The results show that permitting greater crossborder transfers and adopting improved technologies could have large spillover multiplier effects on overall economic welfare in the region. And simply reducing African countries’ trade barriers and improving cross-border transport could increase agricultural incomes by as much as 10%. These two examples confirm that regional cooperation in agricultural research and harmonization and liberalization of regional trade systems are two important areas that have yet to be optimally harnessed to generate larger spillovers and enhance regional economic take-off.