Background: Adolescents are required to take increased responsibility for their health. Although health literacy is implicated in adults' health decision-making and health behaviors, little is known about adolescents' health literacy and its relationship to their health behaviors. Furthermore, adolescent health literacy research overlooks adolescent development-specific needs and skills. Therefore, we qualitatively explored adolescents' (1) definitions of health literacy, preventive health behaviors, and health risk behaviors; and (2) perception of the health literacy/health behavior relationship. Methods: Six semi-structured focus groups were conducted with adolescents (N = 37) who answered questions about their perceptions of health literacy, preventive health behaviors, and health risk behaviors. Focus groups were coded using thematic analysis. Themes representing adolescents' definitions of health literacy were secondarily coded for alignment with definitions in the literature. Results: Some of adolescents' health literacy definitions aligned with the adult health literacy literature. They considered health literacy a tool for informed decision-making, but acknowledged not always using these skills. Conclusions: Adolescents' definitions of health literacy were multidimensional, going beyond numeracy and literacy skills. Developmental characteristics and adolescents' definition of health risk behaviors were related to use of health literacy skills. Opportunities for adolescents to develop and practice health literacy skills are discussed.