Terror management theory posits that death-related threats increase people’s investment in religious activity, dedication, and belief. Given that war usually results in deaths, the authors hypothesized that war, as a death-related threat, would be associated with greater religiousness. The present research assessed this hypothesis with a large worldwide sample (N = 86,272). Using the Global Peace Index and World Value Survey, the authors found that people were more religious (i.e., religious practice, religious identity, and belief in God) when their countries and districts suffered from more wars/conflicts. The positive relationship between war and religiousness was partially explained by worries about war. That is, people in countries with existing war/conflict experienced higher levels of worries about war and, in turn, showed increased religiousness.