In what way can societal actors in transitional polities play a role in influencing bilateral economic agreements? Societal actors are often ignored in the state-centric international relations literature. We, however, contend that social resistance to a foreign development project can reshape the international outcome, even under an asymmetric bargaining structure, if two conditions are met: the host country’s policy options are conditioned by citizens’ resistance; and the home country is eager to continue cooperation. To make this argument, this paper examines the social resistance to the China-backed Letpadaung copper mine in Myanmar amid the host country’s democratisation. Employing a process-tracing technique and drawing upon extensive interviews from 2015–2019, official documents and secondary data, we argue that a popular anti-mining movement transformed a previous state-to-state bargaining process into a two-level game negotiation. As a result, the rise of societal actors was able to disrupt project implementation and extract concessions from China in exchange for project resumption.