Models of collective action rarely account for differences across individuals beyond a limited set of strategies, ignoring variation in condition, motivation and personality. However, emerging evidence from the field of animal behavior indicates that these differences may have significant implications for the dynamics of collective action. For example, inter-individual differences within groups can generate leader-follower relationships that are integral to successful collective action. This research has only recently been extended to humans and non-human primates and has yet to be united into a single explanatory framework. This symposium aims to capture the breadth of inter-individual differences as they relate to collective action in humans and non-human primates. We bring together researchers studying diverse primate species and small-scale societies to present data on inter-individual differences in collective action. This symposium will 1) delineate similarities and differences in collective action across primates; 2) identify how inter-individual differences contribute to inter-specific differences in collective action; 3) explore how these data fit within the existing body of work on collective action; 4) and discuss how systematic cross-cultural and cross-specific comparisons might be made for future research.