jats:p We present a largescale, preregistered examination of factors that explain why citizens of certain nations might show higher levels of national narcissism than others. National narcissism is the belief that one’s nation is exceptional yet undervalued. It is related to several social ills, including conspiracy beliefs, intergroup aggression, extremism, and rejection of science. We theorized that national narcissism would be related to the nature of relations between countries. We expected it to be associated with higher levels of external conflict and lower levels of globalization. Using multilevel modeling across 56 countries ( n = 50,757), we found that citizens of less globalized nations showed higher average national narcissism. However, external conflict was unrelated to national narcissism. We also tested whether citizens’ national narcissism was higher in countries led by populists but found no evidence for this effect. At the individual level, higher individual narcissism, self-esteem, and right-wing political orientation positively predicted higher national narcissism. </jats:p>