Adolescents are prone to mental disorders and decreased quality of life due to excessive use of social media. Excessive use can cause stress and anxiety that impacts their well-being. This study aims to determine the relationship between social media use and adolescent mental health and quality of life at SMA Negeri X Denpasar. This study used a quantitative descriptive method with a cross sectional approach on 212 students with purposive sampling. The instruments used were SIPMS, SDQ, and WHOQOL-BREF, with MANOVA analysis to simultaneously assess the influence of social media use on both dependent variables. The results of the study showed that the average use of social media was 37.94 in the medium category, mental health was 23.07 in the abnormal category, and the average quality of life was 93.46 in the medium category. p = 0.876 >0.05 which shows that there is no significant relationship between social media use and mental health and quality of life simultaneously. This study shows that the level of social media use does not have a significant influence on mental health and quality of life. The majority of students use social media adaptively so that it does not trigger welfare disorders. The results of this study confirm that other factors outside of the use of social media play a greater role in influencing the mental condition and quality of life of adolescents.