Mental illnesses are the leading cause of disease burden among children and young people (CYP) globally. Low- and middle-income countries (LMIC) are disproportionately affected. Enhancing mental health literacy (MHL) is one way to combat low levels of help-seeking and effective treatment receipt. We aimed to synthesis evidence about knowledge, beliefs and attitudes of CYP in LMICs about mental illnesses, their treatments and outcomes, evaluating factors that can enhance or impede help-seeking to inform context-specific and developmentally appropriate understandings of MHL. Eight bibliographic databases were searched from inception to July 2020: PsycInfo, EMBASE, Medline (OVID), Scopus, ASSIA (ProQuest), SSCI, SCI (Web of Science) CINAHL PLUS, Social Sciences full text (EBSCO). 58 papers (41 quantitative, 13 qualitative, 4 mixed methods) representing 52 separate studies comprising 36,429 participants with a mean age of 15.3 [10.4–17.4], were appraised and synthesized using narrative synthesis methods. Low levels of recognition and knowledge about mental health problems and illnesses, pervasive levels of stigma and low confidence in professional healthcare services, even when considered a valid treatment option were dominant themes. CYP cited the value of traditional healers and social networks for seeking help. Several important areas were under-researched including the link between specific stigma types and active help-seeking and research is needed to understand more fully the interplay between knowledge, beliefs and attitudes across varied cultural settings. Greater exploration of social networks and the value of collaboration with traditional healers is consistent with promising, yet understudied, areas of community-based MHL interventions combining education and social contact.

Background: Mental illnesses are the leading causes of global disease burden. The impact is heightened in low‐ and middle‐income countries (LMICs) due to embryonic care systems and extant barriers to healthcare access. Understanding children and adolescents' conceptualisations of mental health wellbeing in these settings is important to optimize health prevention and promotion initiatives.Objective: To systematically review and synthesize children and adolescents' conceptualisations and views of mental health and wellbeing in LMICs.Design: Ten databases were systematically searched from inception to July 2020 and findings from included studies were synthesized.Results: Twenty papers met eligibility criteria comprising qualitative, quantitative and mixed methods studies. Children and adolescents identified aspects of mental health and wellbeing, including positive affect and outlook and having sufficient personal resources to face daily challenges. Identified factors recognized the importance of activating both kin and lay networks in supporting and maintaining wellbeing. Conceptualisations of mental health and wellbeing were varied and influenced by culture, developmental stage and gender.Discussion and Conclusions: Irrespective of environmental and sociocultural influences on concepts of wellbeing and mental health, children and adolescents in LMICs can conceptualise these constructs and identify how they pursue positive mental health and wellbeing important for developing age and culture‐appropriate community mental health strategies. Our review highlights the need to extend inquiry to wider developmental stages and both across and within specific populations in LMICs.Patient and Public Involvement: Initial results were presented at stakeholder workshops, which included children, adolescents, parents and health professionals held in Indonesia in January 2019 to allow the opportunity for feedback.