Objectives: To examine the ability of four models of behaviour, namely, Protection Motivation Theory (PMT), the Common Sense Self-Regulation Model (CS-SRM), and Social Cognitive Theory and the Reasoned Action Approach (SCT and RAA) to understand adherence to transmission-reducing behaviours (TRBs) advised by national governments for suppression of SARS-CoV2. Design: A series of six cross-sectional telephone surveys of a random representative sample of adults living in Scotland. Methods: Self-reported adherence to three TRBs (physical distancing, wearing a face covering and handwashing), PMT, CS-SRM, and SCT/RAA constructs, and sociodemographic variables were measured each week for 6 weeks (n = ~500 p/w; third June–15th July) via a 15 min telephone survey. Results: Adherence was high (‘Always’ or ‘Most times’) throughout for physical distancing and handwashing, and, when mandated, for wearing a face covering. Older people were more adherent to all TRBs. Constructs from all three models predicted all three TRBs. Intention and self-efficacy (SCT/RAA) were the only beliefs to predict to all three TRBs each week and for all groups equally; intention was the strongest predictor. The predictive utility of PMT and CS-SRM varied by TRB and by group. Of note was the observation that several illness beliefs were associated with adherence only for those who believed they had not had COVID-19. Conclusions: The CHARIS project has identified beliefs about specific behaviours, the illness and the risks associated with lower adherence rates that might be addressed in national interventions. It confirms previous findings that some groups show lower levels of adherence and might be specially targeted.