Social media is integral to modern life, particularly for adolescents who spend considerable time online. However, excessive use poses significant risks to well-being, especially among adolescents who are vulnerable to compulsive social media usage. This study examines factors contributing to social media addiction among Vietnamese adolescents using the Bergen Social Media Addiction Scale (BSMAS) and the Online Fear of Missing Out Inventory (On-FoMO). A cross-sectional study was conducted in Vietnam with participants aged 13 to under 18. Snowball sampling was used to ensure a diverse participant pool. The study excluded individuals with diagnosed mood disorders to maintain population homogeneity. BSMAS, On-FoMO, demographic data, and informed consent were collected via an online survey. The study found a high prevalence of social media addiction among Vietnamese adolescents, with females being more susceptible than males. Vietnamese adolescents struggled to reduce social media usage and felt distressed when restricted. They did not necessarily feel envious or sad when seeing others' happiness online, nor did they seek validation through likes or comments. However, Vietnamese adolescents reported forgetting problems or being late due to SM use. The study results indicate that improving 17 emotional intelligence scales may reduce the extent of SMA among Vietnamese adolescents. The study results also suggest that interventions for social media addiction need to be developed in different fields.