Social media addiction is increasingly recognized for its psychological and socio-economic impacts, such as impaired social relationships, academic underperformance, anxiety, and depression. While research on this phenomenon is emerging in Nigeria, there remains a gap in understanding the predictive role of social anxiety, personality traits, and self-esteem, especially among workers and students in higher institutions. This study examines how social anxiety, personality traits and demographics (age and gender) predict social media addiction. This study addresses this gap by employing a cross-sectional quantitative survey with 397 participants in Plateau State. The study made use of the social cognitive theory to explain this phenomenon. Three Hypotheses were tested. Social anxiety did not significantly predict social media addiction (β = .120, R² = .014, p > .05), suggesting it has no influence in this context. Personality traits, however, were significant predictors (R = .18, R² = .032, p  .05; gender: t (397) = 1.017, p > .05).This study recommends tailored interventions, additional research, and application of findings in practice to better address social media addiction among Nigerian workers and students.