This essay introduces the political market framework (PMF) and discusses its implications for understanding local sustainability policy. The PMF conceptualizes public policy related to sustainability as the product of exchange between governmental policy suppliers and voter and interest group policy demanders. After presenting a political market model, the role of political institutions is introduced. Institutions structure exchange relationships by determining transaction costs of searching for mutually beneficial agreements, bargaining over outcomes, and monitoring and enforcing decisions. The central implication for research is the need to account for the moderating role that political institutions play in sustainability policy decisions. A research agenda based on the PMF is advanced. The conclusion addresses the limitations of the framework as well as its implications for policy adoptions, program designs, and individual behavior.