Making sense of human actions involves thinking about both "endogenous" influences (the internal mental states of agents) and "exogenous" influences (social, moral, and interpersonal constraints). Culture impacts how we weight the relative causal influence of these two influences. To examine these cultural influences in depth, we asked 147 4-11-year-olds in 3 cultural groups (Singaporean Chinese, Singaporean Malay, and U.S. Americans) about the possibility of acting on desires that go against social, moral, and interpersonal norms (i.e., "free will," defined as the ability to do otherwise). By age 4, U.S. children were more likely to endorse the freedom to act against norms than Singaporean children, and these cultural differences were more prevalent at older ages. Children's explanations mirrored between- and within-culture differences in causal beliefs about action: Both groups of Singaporean children referenced interdependent causes/consequences in their explanations than U.S. children, and Singaporean Malay children referenced more interdependent causes/consequences than Singaporean Chinese children. Singaporean children were more likely to elaborate on lack of free will by referencing punishment and/or having to seek permission from authorities, revealing a local cultural influence of growing up in an authoritarian society. These results underscore the critical role of culture in shaping how children understand mind, self, and action.