To what extent or in what circumstances might ‘smart policy mixes’ be invoked in transnational governance rather than just as an approach to instrument and policy design at a domestic level? In the environmental context, policy mixes have been examined within the spheres of private standards and public-private partnerships (and their interactions with other instruments and actors), but there has been no comparable work on equally important “deep green” initiatives that emphasize confrontation and conflict rather than partnerships and cooperation. This Chapter is concerned with one ‘deep green’ transnational initiative that has had a remarkable impact within a relatively short period and provides insights into the potential for ‘smart mixes’ in the transnational context: the global fossil fuel divestment movement. It examines the transnational dimensions of climate governance through the lens of the divestment movement, with a focus on the movement’s interactions with and impact on a cluster of other climate change actors. It also asks the normative question of what smart mixes should be invoked in this context, as well as whether, to what extent and in what ways the insights of smart regulation in the domestic context are capable of extrapolation to transnational governance.