Psychosocial and mental health problems are quite prevalent among adolescent worldwide, some data reporting up to 20% of adolescents having such problems. A number of risk factors, familial, individual and societal, have been indentified as contributing to these problems in adolescents. There are also many factors, such as family and societal connectedness, that protect adolescents from engaging in health risk behaviors that lead to psychosocial and mental health problems. A careful psychosocial assessment should be an essential part of adolescent health care. This paper provides a brief review of the principles of psychosocial assessment of adolescents.