ABSTRACT Rationale: Understanding the impact of different sport initiatives on young people from socially vulnerable backgrounds is important. However, there remains a paucity of quantitative research on the quality of life of this group. Method: This study employed an ex post facto observational design to provide data on health-related quality of life (HRQoL) from socially vulnerable Brazilian adolescents enrolled in a community soccer program (“Union Project”). Male soccer players (n = 26, 2x/week for 6 months in the soccer program) and non-players (n = 26, no participation in sports program) were included in the study. Participants answered a form about sociodemographic data and health-related quality of life perception (KIDSCREEN-27). Differences in HRQoL between players and non-players were verified by the independent t test and the effect size was estimated (Cohen’s d). Findings: Except for the School Environment dimension, soccer players presented statistically higher scores of HRQoL in comparison to non-players (P < 0.05). The Physical Well-Being dimension (d = 1.9) and the total HRQoL (d = 1.4) showed large effects in favor of the soccer player group. Research contribution: The Union Project seems to have the potential to improve the HRQoL of socially vulnerable adolescents, in which soccer players showed better scores on almost all dimensions of HRQoL compared to their peers.