Favourable policy environments stimulate economic growth, while unfavourable policy regimes stymie development outcomes. As policy decisions shape the incentives and actions of key farmer, consumer and industry groups, policies become central determinants of overall economic performance as well as progress towards key agricultural, nutrition and food security goals. The Kaleidoscope Model (KM) provides a simple, applied framework for analysing the key drivers of policy change in food security, agriculture and nutrition. This chapter describes the KM, including its origins, premises and applications. The discussion presents several practical KM tools for stakeholders interested in using the KM to improve policy system performance or those aiming to intervene more effectively in a specific policy setting.