Introducing additional constructs to the theory is one approach to increasing explained variance in health behavior. For example, researchers have examined relations between moral norms, an additional form of normative influence, and health behavior. Moral norms are considered particularly relevant when there is a moral imperative for acting (e.g., vaccination and blood donation) [17]. In the context of COVID-19, messaging from public health authorities on COVID-19-preventive behaviors has focused on protecting the vulnerable (e.g., immunosuppressed individuals, those with underlying health conditions, and the elderly) [3]. On this basis, we reasoned that moral norm would constitute a highly relevant determinant of social distancing intention and behavior in the context of the pandemic. In addition, anticipated regret has been shown to predict behaviors perceived likely to have adverse consequences or result in significant losses if not performed [17]. Failure to perform social distancing behaviors may be perceived as having highly undesirable consequences, such as becoming infected or infecting vulnerable others. We, therefore, included moral norm and anticipated regret as additional predictors of intention to perform social distancing behavior in our integrated model.