Globalization magnifies the problems that affect all people and that require large-scale human cooperation – for example, the overharvesting of natural resources and human induced global warming. But what does globalization imply for the cooperation needed to address such global social dilemmas? Two competing hypotheses are offered. One hypothesis is that globalization prompts reactionary movements that reinforce parochial distinctions among people. Large-scale cooperation then focuses on favoring one’s own ethnic, racial or language group. The alternative hypothesis suggests that globalization strengthens cosmopolitan attitudes by weakening the relevance of ethnicity, locality or nationhood as sources of identification. In essence, globalization – the increasing interconnectedness of people worldwide - broadens the group boundaries within which individuals perceive they belong. We test these hypotheses by measuring globalization at both the country and individual levels and analysing the relationship between globalization and individual cooperation with distal others in multi-level sequential cooperation experiments in which players can contribute to individual, local and/or global accounts. Our samples were drawn from the general populations of the United States, Italy, Russia, Argentina, South Africa, and Iran. We find that as country and individual levels of globalization increase, so too does individual cooperation at the global level vis-à-vis the local level. In essence, ‘globalized’ individuals draw broader group boundaries than others, eschewing parochial motivations in favor of cosmopolitan ones. Globalization may thus be fundamental in shaping contemporary large-scale cooperation, and may be a positive force toward the provision of global public goods.