We take an ethics theory perspective to examine rule violations and workarounds in the UK construction industry in the context of the COVID-19 pandemic. The UK construction sector remained largely operational during lockdowns in the UK, providing an opportunity to explore the ways in which construction workers made ethical decisions in situ, related to health and safety at work, and COVID-19 rules. We conducted 22 semi-structured interviews with participants from 11 organisations (3 major construction companies and 8 subcontractors) during November 2021 to January 2022. Our qualitative analysis focused on coding responses based on the use of moral disengagement tactics, and the dimensions of moral intensity (magnitude of consequences, social consensus, probability of effect, temporal immediacy, proximity and, concentration of effect). We found instances of ethical dilemmas, including conflicts between compliance with organisational health and safety rules, and following COVID-19 rules. Our analysis showed that rule violations were often justified based on moral disengagement tactics, particularly cognitive reconstrual, obscuring personal agency, disregarding consequences and vilification of the victims. Furthermore, moral intensity played a significant role in making ethical decisions about violating rules. Moral intensity was most influential (across dimensions) for moral disengagement based on cognitive reconstrual (e.g., justifications for choosing to follow one set of rules over another). Social context was highly influential in workers’ ethical decisions, including organisational and group social norms, but wider societal attitudes towards the COVID-19 pandemic, also played a significant role. We discuss the implications for business ethics theory, policy and practice, including recommendations for businesses and policymakers.