To reduce the impact of communicable diseases like COVID-19, collective action is required and likely to be susceptible to normative influence as well as whether people are more or less collectively oriented. We extend the theory of normative social behavior (TNSB) to account for group orientation and predict the relationships between social norms and physical distancing behaviors. Using a rolling cross-sectional design during 17 weeks of the pandemic, a national sample of US residents from 20 states (N = 8,778) participated in the study. The findings show that perceived descriptive norms, injunctive norms, and group orientation are significantly associated with physical distancing. The descriptive norm-behavior relationship and injunctive norm-behavior relationship are moderated by group orientation and the other predicted moderators in the TNSB. The findings extend the TNSB and highlight the need to understand social norms and group orientation in formative research for health communication campaigns designed to promote prevention behaviors.