Introduction: Social media is embedded in adolescents' daily routines, and concerns have grown about its links with loneliness, a common social-emotional challenge in this period. Clarifying whether general exposure or dysregulated engagement is more relevant may explain when and how social media relates to loneliness.


Purpose: This meta-analysis estimates the association between social media use and loneliness, contrasts engagement patterns (problematic use, time spent, active use, and passive use), and tests moderation by geographic region, gender, and study year.


Method: We searched six databases from January 2000 to May 2025 for studies reporting associations between social media use and loneliness among adolescents or emerging adults. The dataset included 59 studies, 67 independent samples, and 81,344 participants (59.5% female; mean age = 17.6 years; range = 12.5-24.9). Random-effects models synthesized effects, and meta-regression tested the moderators. Engagement patterns were modeled separately to reduce construct confounding.


Results: Problematic social media use showed a moderate and consistent association with greater loneliness (r = 0.29, 95% CI [0.22, 0.35], p < .001). Time spent on social media was positively but more weakly related to loneliness (r = 0.07, 95% CI [0.01, 0.12], p = .014). No reliable differences emerged between active and passive use in their associations with loneliness. Meta-regression indicated no significant moderation by geographic region, gender, or study year, which implies broad generalizability across the contexts and cohorts sampled to date.


Conclusion: Differentiating normative time-based exposure from problematic engagement is essential when evaluating psychological correlates of social media use. The results point to mechanisms such as social comparison, displaced offline connection, and difficulties with emotion regulation as promising explanatory targets. Future longitudinal and experimental studies should clarify causal pathways and guide developmentally appropriate interventions to reduce loneliness in adolescence.