An individual development stage is adolescence, a phase characterized by rapid physical, emotional, and social changes. Adolescence is the transition phase from 10 to 19 years of age. During this phase, adolescents can face challenges in their academic as well as social and personal lives that can lead to different mental health issues like anxiety, stress, and depression. World Health Organization (WHO) reports that over 10% of adolescents worldwide suffer from mental health disorders that are not adequately addressed. This study examines adolescents' mental health and the factors influencing it in Southeast Asia. The research approach used was a systematic review, by conducting literature searches on the internet via the PubMed, ProQuest, and EBSCO databases. A systematic review of 8 articles was performed based on inclusion and exclusion criteria. The research results show prevalence of adolescent mental health problems in Asia is high and affects socioeconomic status, level of academic achievement, psychosocial status, and gender gaps. Risk factors include bullying, loneliness, smoking, and social isolation; positive relationships with family and school are protective. Stigma is still part of the picture, but there is quite a bit of mental health literacy. Depression, anxiety, PTSD, suicide, and substance abuse are significant public health challenges across Southeast Asia.