peer reviewed ; Background: The Dual Factor Model (DFM) of mental health incorporates both subjective well-being (SWB) and psychopathology symptoms, proposing a more comprehensive approach to mental health. As such, four groups can be distinguished in accordance with the level of SWB and psychopathology symptoms: 1. complete mental health; 2. incomplete mental health; 3. incomplete mental illness; 4. complete mental illness. Social support and loneliness are known to influence both SWB and psychopathology symptoms. The aim of this study is to explore the odds of different sources of support and loneliness in the different mental health groups, as proposed by the DFM, in adolescents in Luxembourg. Methods: A total of 7201 adolescents aged 11 to 18-years old participated in the 2022 Health Behaviour in School-Aged Children in Luxembourg. In order to categorize the DFM mental health groups, SWB was measured using the WHO-5 Index and anxiety symptomatology (GAD-2) was used for psychopathology symptoms. Social support (from family, peers, teacher and classmates) and loneliness were analyses using a multinomial logistic regression, adjusting for age, gender, family affluence and family composition. Results: Adolescents who perceive a low (in comparison to good) classmate support and teacher support and feel lonely have an increasing chance of being in the Incomplete Mental Health, Incomplete Mental Illness and Complete Mental Illness (e.g. classmate support: OR = 1.69, OR = 2.19 and OR = 2.79, respectively). Discussion: The lack of support from the school sources and feeling loneliness are the most important factors increasing the probability to be part of the Complete Mental Illness group. Prevention strategies should focus on improving the school setting conditions. School is a privileged place for health promotion, offering a comprehensive, sustained and effective means of intervention for the target population.