Fifty years ago, the main challenges to large infrastructure projects were technical or scientific. Today, the greatest hurdles faced by such projects are almost always social and/or political. Whether constructing large dams in the developing world or siting liquefied natural gas terminals in the United States, the onset of these projects often triggers intense popular opposition. But not always, and therein lays the animating aim of this project. We undertake a systematic comparative case analysis of mobilization efforts against 11 oil and gas pipeline projects spanning 16 countries in the developing world. Using theories from the social movement and facility siting literatures and the technique of fuzzy set/qualitative comparative analysis (fs/QCA), we examine the causal conditions linked to political and legal opposition to these projects. We find that both Western funding of projects and public consultation serve as necessary political opportunities encouraging mobilization. In addition, not compensating the host country for involvement in the project is linked to mobilization. Finally, some risk from the project, in the form of environmental or social impact, is associated with mobilization; however, this impact does not have to be very significant for mobilization to occur.