BackgroundDefinitions and perceptions of health and mental health have not remained static over time. This is also true for statistics over Swedish children's and adolescents' health and mental health status. The majority of Swedish school-aged children and adolescents report good physical health and good life satisfaction. However, there are some warning signs when it comes to children's and adolescents' health and mental health status, for instance, an increased overweight or obesity in children and adolescents, as well as a higher proportion reporting psychological problems and stress. There is also a need for knowing more about the younger population's voices in this matter. The aim was therefore to explore children's and adolescent's conceptualizations and perceptions of health in general, and mental health in particular.MethodsOpen semistructured group interviews with 44 Swedish children and adolescents (10-14 years old) recruited from four schools were conducted. The interviews were conducted between April 2022 and January 2023. Data were analyzed with qualitative content analysis.ResultsChildren's and adolescents' conceptualizations of health included aspects of both the body and the mind, with a focus on the latter. Mental health was expressed as a state of being, illustrated by various lived experiences of emotions, moods, and thoughts. The social world was ever present in their understanding of health, e.g., through the lenses of social and gender norms.ConclusionsThis study revealed children's and adolescents' recognition of health terms and their ability to observe nuances between mental health problems and everyday struggles. The participants discussed mental health problems to a greater extent than positive mental health. An implication of this study is the highlighted need to focus more on mental health promotion in future preventive programs. These findings might potentially influence how school staff and student health teams communicate with children and adolescents about these concepts.