school characteristics and avoid biased estimates, controlling for age, gender, and frequency of social media use. sampling weights and 95% confidence intervals are shown. P-values are shown for interaction effects, where low-SES between PSMU and wellbeing is stratified by SES. use increases, except in Mediterranean countries, Yet, this relationship differs depending on the significant differences across SES groups. psychological complaints, SES gaps are small across regions, except for the Anglo-Celtic region, where low-SES adolescents experience a across all 43 countries in our study. SES differences problematic use rises. For life evaluation, we country. For psychological complaints, statistically most regions, with lower-SES adolescents showing