Purpose The study explores how social media impacts institutional trust through the lens of Kohlberg’s stages of moral development. Specifically, this study aims to understand how moral relativism and moral intuitionism can moderate the relationship between social media use and perception of social authorities. Design/methodology/approach The study analyzes a large data set from the World Values Survey, covering responses from approximately 52,000 individuals across 45 countries between 2017 and 2022. Multiple regression analyses were conducted to test for interactions between social media use and stages of moral development on trust in social institutions. Findings The study finds that different stages of moral development significantly moderate the relationship between social media use and institutional trust. Specifically, higher moral development buffers the negative effect of social media use on trust in three main social institutions: law enforcement, parliament and the legal system. In contrast, individuals with higher levels of moral relativism and moral intuitionism are more susceptible to the negative influence of social media on institutional trust. Research limitations/implications The study relies on self-reported data from the World Values Survey, which may introduce response biases. In addition, while the large-scale data set offers insights into correlations, it does not allow for conclusive causal inferences. Originality/value This research contributes to understanding technology’s impact on modern societies by highlighting the role of individual moral development in shaping perceptions of key social institutions. The study uniquely integrates Kohlberg’s moral development theory with the influence of social media, offering a novel perspective on how personal moral systems can moderate the effect of digital media use.