This study analyzes the influence of social determinants (SD) and positive youth development (PYD) on the mental health (MH) of Chilean adolescents. A nonexperimental, cross-sectional, correlational-explanatory design was adopted to analyze data from 612 adolescents (43.46% males and 56.54% females) aged between 11 and 19 years (M = 14.92, SD = 1.50). The SD evaluated included parental educational level, family affluence, gender, migratory status, and ethnicity. PYD was assessed via the 5Cs model (Competence, Confidence, Connection, Character, and Caring). MH was conceptualized through the dual-factor model, which encompasses positive mental health (PMH) and negative mental health (NMH). The analyses included confirmatory factor analysis to assess the measurement models and structural equation modeling to examine the direct and indirect effects of the hypothesized relationships. The findings indicate that family affluence and gender are the factors most consistently associated with the dimensions of PYD and MH. Confidence and connection positively influence MH, improving PMH and reducing NMH, and mediate the relationship between SD and MH. The importance of considering the socioeconomic context and individual capabilities in mental health promotion strategies is highlighted, proposing an integral approach that addresses both the positive and negative aspects of adolescent well-being.