--- - |2 Abstract When and how do social movements form to mobilize action across national boundaries? In the context of the 2015 movement to support Syrian refugees, we develop an integrative model of transnational social movement formation shaped by pre‐existing world‐views (social dominance orientation and right‐wing authoritarianism) and social media exposure to iconic events, resulting in an emergent group consciousness (“we are”, “we believe”, “we feel”). Group consciousness is, in turn, the proximal predictor of solidarity with refugees. Participants were from six countries: Hungary (N = 267), Romania (N = 163), Germany (N = 190), the United Kingdom (N = 159), the United States (N = 244) and Australia (N = 344). Multi‐group structural equation models confirmed that group consciousness, shaped by individual differences and exposure to events through social media, was the proximal predictor of solidarity. The subjective meaning of group consciousness varied across samples, reflecting national differences. Results support the importance of considering individual and national differences, and group processes in understanding emergent social movements. - European Journal of Social Psychology, EarlyView.