Many controversial immigration policies have recently emerged across the United States and abroad. We explore the role of national context in shaping support for such policies. Specifically, we examine whether the extent to which ideological attitudes—Right-Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO)—predict policy support is moderated by the national context of the policy. Across three studies, United States citizens read about a controversial immigration policy affecting either their own country (United States) or a foreign country (Israel or Singapore) and indicated their support for the policy. Results reveal that SDO predicts policy support, regardless of its national context; this effect is mediated by perceived competition. Conversely, RWA predicts policy support only if the policy affects domestic immigration; this effect is mediated by perceptions of cultural threat. Consistent with prior research, the present findings highlight the role of perceived cultural threat to one's ingroup and perceived competition in shaping attitudes toward immigration and shed light on some of the motivations underlying the recent rise in popularity of strict immigration policies.