During the novel coronavirus pandemic, early data suggested that men were slightly more likely to contract COVID-19 than women, less likely to seek medical attention for the disease, and far more likely to die as a result of COVID-19. While several studies have explored this gender gap, none has attempted to isolate the psychological processes underpinning this phenomenon. In this research note, I suggest that sexism partly explains these differences. Using data from a large (N = 100,689) survey of American adults conducted between March and June 2020 by the Democracy Fund and the University of California, Los Angeles (Nationscape), I find that sexist beliefs, a component of masculine norms, are consistently the strongest predictor of coronavirus-related emotions, behaviors, policy attitudes, and ultimately contracting COVID-19. This study highlights how gender ideology can impact health and impede government public health efforts.