THE RELATIONSHIP BETWEEN DEPRESSION, ANXIETY, STRESS AND INTERNET USE AMONG HIGH SCHOOL STUDENTS The prevalence of mental health issues among high school students has raised concerns globally, with depression, anxiety, and stress being common challenges. This study investigates the relationship between depression, anxiety, stress, and internet use among high school students in Da Nang, Vietnam. The short Internet Addiction Test (s-IAT) and Depression Anxiety Stress Scales (DASS-21) were used to assess internet addiction and mental health symptoms. Data were analyzed using correlation analysis and regression models. Results revealed significant positive correlations between internet use and symptoms of stress, anxiety, and depression, highlighting the importance of addressing problematic internet usage patterns. Additionally, associations were found between demographic variables, such as parental occupations and socioeconomic status, and mental health outcomes, emphasizing the interconnected nature of individual, familial, and societal factors. The study underscores the need for targeted interventions to promote healthy internet habits and mitigate potential harms among high school students. By understanding the complex interplay between internet use and mental health outcomes, stakeholders can develop effective strategies to support the well-being of adolescents in an increasingly digital world. This research contributes to a deeper understanding of the socio-ecological factors shaping adolescent mental health and informs future intervention efforts. ASEAN Journal of Psychiatry, Vol. 25 (6) June, 2024; 1-16.