In sub-Saharan Africa, crop diversification features prominently in many countries’ climate change adaptation strategies. This study focuses on the determinants of adoption and on the impact of seven cropping systems in Malawi, Mozambique, and Zambia. The work finds that the selection of a high volatile or low productive cropping system increases smallholders’ vulnerability and exposure to food insecurity. The findings suggest that policies supporting private agricultural input and output market development are critical for inducing adoption of more diverse, resilient, and profitable cropping systems. Finally, the brief shows that while parastatal institutions may encourage the adoption of maize mono-cropping systems reducing the local level of diversification, the implementation of land policies ensuring land-availability and security may be critical for incentivizing the adoption of more productive and resilient systems. The results can be employed by policy makers, partners, and other practitioners to favour the implementation of more resilient systems and to support farmers with a set of policy options during period of high income volatility.