Health literacy is a critical driver of achieving an equitable world for every child and adolescent. Although the relationship between health literacy and health-related quality of life (HRQoL) has been documented, little is known among adolescents. In addition, due to lack of theory-driven empirical research, it remains unknown about the full relationship between health literacy, its antecedents, and HRQoL. This study aimed to apply Manganello's framework to investigate how health literacy was associated with its antecedents and HRQoL in Beijing secondary students. A cross-sectional study was conducted with 650 students in years 7 to 9 from four secondary schools in Beijing. Based on Manganello's health literacy framework, a self-administered questionnaire was used to collect information on health literacy, its antecedents (i.e., sociodemographics, self-efficacy, social support, school and community environment), and HRQoL. The 8-item Health Literacy Assessment Tool was used to measure health literacy (score range 0-37), and the KIDSCREEN-10 was used to measure HRQoL (score range 10-50). Path analysis was conducted to examine the mediating role of health literacy in the relationship between its antecedents and HRQoL. Overall, the average score of students' health literacy and HRQoL was 26.37 (±5.89) and 37.49 (±5.78), respectively. Health literacy was positively correlated with HRQoL (r = 0.36, p < .01). In the final path model, health literacy was not associated with HRQoL. However, students' social support, school environment, and community environment were associated with HRQoL. Health literacy was affected by self-efficacy, social support, and school environment (all p < .05). A range of intrapersonal, interpersonal, and environmental factors were associated with health literacy and HRQoL. A holistic approach is needed to improve health literacy and HRQoL through multilevel intervention strategies such as increasing personal self-efficacy, promoting social support, and creating positive environments. [HLRP: Health Literacy Research and Practice. 2022;6(4):e300-e309.] Plain Language Summary: We investigated how health literacy was related to its influencing factors and HRQoL among Beijing secondary students in years 7 to 9. Health literacy and HRQoL were independent outcomes affected by a range of social-ecological factors including self-efficacy, social support, and perceptions of school and community environments.