["Journal for the Scientific Study of Religion, EarlyView. ", "\nABSTRACT\nHow do religious rules and regulations affect behavior? We examine this question using changes in Catholic regulations during the Covid‐19 pandemic combined with mobility data from 15 million smartphone users from 2019 to 2022. We first document overall trends: Total religious attendance declined sharply in March 2020 and thereafter recovered slowly and more gradually than other activities like restaurant visits. There were also variations across religious groups, with Catholics returning at a slower pace than Protestants, Orthodox Christians, Jews, Muslims, Hindus, and Buddhists. We then introduce a novel approach to examine the impact of religious policies on behavior, leveraging variations in the timing of dispensation rescissions (requirements for Sunday attendance) by US Catholic bishops. Using a difference‐in‐differences event study model, we find a short‐term 2–4 percentage point increase in Catholic weekend church attendance following the lifting of dispensations, compared to the 2019 baseline. However, this effect fades over time and is smaller than the attendance surge seen after reopening churches post‐lockdowns. These results suggest that religious policies impact behavior, though their effects may be transient."]