This chapter provides an overview of the literature that associates religiosity and religious affiliation with the prevalence and severity of COVID-19. It first discusses studies on the interplay between religiosity, health outcomes, COVID-19 spread, compliance with vaccination policies, and trust. The chapter then focuses on methodological challenges in exploring the religiosity-COVID-19 relationship and reviews the literature that uses data from different world regions. The empirical literature suggests that in regions where individuals manifest a higher degree of religiosity, the COVID-19 mortality rates are conditionally higher. Interestingly, the correlation between religiosity and COVID-19 mortality rates is particularly strong in Protestant and Catholic regions, while weaker for other denominations. Thus, it can be conferred that religious denomination and the degree of religiosity Religiosityplay an important role in the spread of the virus. A hypothesized mechanism is that in regions with a high degree of religiosity, the social interactions are more intense, particularly those driven by higher religious attendance, suggesting that these aspects should be embedded in policies with the aim of maximizing their effectiveness for future disease outbreaks.