Civic engagement is crucial to society, particularly during a health crisis, but little is known about its antecedents. To address literature gaps, this study explores how procedural fairness, trust in public authority, and generalized social beliefs impact civic engagement during the COVID-19 pandemic in Macao, China, which accommodates the highest population density globally. We surveyed 1011 Chinese adults (61.2% women; 18–94 years old) by telephone using a two-step cluster random sampling method. As hypothesized, procedural fairness, trust in public authority, and the generalized social beliefs about social complexity positively influenced civic engagement intentions (r =.17 to.32, p <.001; regression: β =.14 to.23, p <.001), mediated by civic engagement attitudes (indirect effect: B = 0.13 to 0.19; β = 0.07 to 0.10; p <.001). Trust in public authority further moderated the effect of procedural fairness on civic engagement attitudes (B = 0.08, β = 0.04, p =.009). Our findings provide a new avenue into understanding the factors underlying civic engagement attitudes and intentions and shed light on tactics for encouraging civic engagement in times of health crisis.