This thesis explains variations in municipal participation in Canada's Partners for Climate Protection Program through an examination of the cases of Calgary and Toronto. I argue that this transnational municipal network and its members employ particular forms of discourse to frame climate change knowledge in a way that reflects the interests and constraints faced by municipal actors. Furthermore, the policy actions advocated by the program and implemented in Calgary and Toronto reflect these interests and constraints by detaching action on climate change from a necessity to respond to the problem, and instead focusing on the benefits of implementing particular solutions. On the one hand, therefore, the interests and constraints at the municipal level determine how the network frames climate change. On the other hand, I argue that this framing results in the need for the program to provide resources to its members in order to encourage participation, and that the perceived value of these resources explains the difference between program participation in Calgary and Toronto. My argument therefore provides an explanation of Partners for Climate Protection participation that considers the influence of both the network and its members in the construction of municipal climate change policy.