There is evidence that many mental health disorders have their origin in adolescence, and that early intervention can improve long-term outcomes. Thus, it is important that adolescents are able to recognise complex indicators of mental health problems that could also be understood in the context of other issues. As such, the objectives of this study were to describe the ability of an adolescent population to recognise and attribute poor school performance, headaches, fatigue, body aches, aggression and violence, to a mental health problem. The common sources of mental health knowledge in this population were also described. This was a descriptive cross-sectional study, conducted in the Sri Jayawardenapura education zone in Sri Lanka, using a structured, pre-tested questionnaire. A multistage cluster sampling method was used with a total sample size of 1002. The results show that poor school work was attributed to a mental health problem by 56% (n=562). The attribution rates for headaches, fatigue and body aches were 42.3%, 32.7%, and 26.5%, respectively. Aggression (64.2%) and violence (66.8 %) was mostly attributed to mental health problems. The main sources of mental health knowledge were subjects taught at school (71.7%) and television (50.9%). Educating adolescents on the possibility of somatic symptoms being part of a mental health problem, and conversely understanding the contribution of other factors to aggression and violence are important. Both traditional and newer forms of media can be utilized for this purpose.