Rapid economic growth has failed to significantly improve poverty and nutrition outcomes in Tanzania. This raises concerns over a decoupling of growth, poverty, and nutrition. We link recent production trends to household incomes using a regionalized, dynamic computable general equilibrium and microsimulation model. Results indicate that the structure of economic growth-not the level-is currently constraining the rate of poverty reduction in Tanzania. Most importantly, agricultural growth trends have been driven by larger-scale farmers and by crops grown in only a few regions of the country. The slow expansion of food crops and livestock also explains the weak relationship between agricultural growth and nutrition outcomes. Additional model simulations find that accelerating agricultural growth, particularly in maize, greatly strengthens the growth-poverty relationship and enhances households- caloric availability. We conclude that low productivity, market constraints (including downstream agroprocessing), and barriers to import substitution for major food crops are among the more binding constraints to reducing poverty and improving nutrition in Tanzania.