Abstract Background The current literature on health literacy rarely considers the views of children and adolescents. The aim of our qualitative evidence synthesis was therefore to develop a child- and adolescent-centered conceptualization of health literacy. Methods We conducted a meta-ethnography of qualitative studies. Our iterative literature search considered the literature up to November 2023. We dually screened 1596 abstracts and 97 full texts, assessed the methodological limitations of the 32 included studies, and considered 21 data-rich studies in the analysis. We extracted first- and second-order constructs, translated the studies into each other, and developed a coherent argumentation. We dually assessed the trustworthiness of the evidence. Results The resulting model comprises micro-, meso-, macro- and chronosystems. It highlights the influence of demographic, cognitive and psychological factors on the development of health literacy in children and adolescents at the micro level, the social environment, including family, friends, peers, teachers, and health professionals at the meso level, and the media and internet, the health and education system, the living environment, and the social narrative about health at the macro level. The chronosystem shows the impact of upbringing, development, and experience. Children absorb health information actively and passively, employing various strategies to evaluate its trustworthiness. They seek advice from their social environment, which acts as a source of information and influencing factor. Different types of information are weighed up and ranked before action is not taken. Conclusions Existing models of health literacy are too one-dimensional to be applied to children and adolescents and do not consider their social and living environment. The proposed model offers a comprehensive understanding of health literacy in children and adolescents. It can be used as a basis for future interventions to improve health literacy. Key messages • Health literacy of children and adolescents is significantly influenced by a combination of internal and external factors. • By incorporating the perspectives of children and adolescents, we have developed a more inclusive and nuanced understanding of health literacy.