This study explores the global diffusion of a new ethical consumption tactic named carrotmob. We trace the spread of carrotmobs from the US across six continents and compare cases of successful and unsuccessful national diffusion. We argue that the heterogeneous spread of carrotmobs cannot be explained solely by differences in individual characteristics of consumers, such as post-materialist value orientation or income, or in the economic opportunity structures, such as national affluence or the availability of environmental labeled goods. Results from semi-structured interviews with organizers and activists in 15 countries suggest that activist brokers relied on social media to influence mobilization, and that social movement organizations, mass media, and governmental organizations played an important role for the diffusion of those collective actions. Our results support theories of connective action and political opportunities, but contradict theories of statism.