Recent scholarship on public integrity has emphasized that the effectiveness of anti-corruption policies depends not only on the existence of formal instruments, but also on their capacity to activate accountability mechanisms from below. Within this framework, this article examines the role of social empowerment as a possible demand-side leverage point and investigates the extent to which its relationship with corruption perceptions is mediated by institutional trust and conditioned by individuals’ sociodemographic position. Using Spanish survey microdata, we estimate a Bayesian structural equation model with moderated mediation and partial pooling by sex, allowing us to assess heterogeneity in the mechanism across age, income, education, and gender. The results show that institutional trust maintains a negative and consistent association with corruption perceptions, whereas the average effect of social empowerment remains limited under assumptions of homogeneity. However, the indirect effect through trust becomes clearly stronger among higher-income individuals and, especially, among older cohorts. Education adds little heterogeneity once material resources are taken into account. Taken together, these findings suggest that empowerment-based strategies may generate unequal benefits unless they incorporate specific measures to reduce activation barriers among more vulnerable groups.