Purpose <p>Health-related quality of life (HRQoL) is key for assessing healthcare outcomes in children and adolescents. The EQ-5D-Y-3&#xa0;L, adapted from the adult version, is widely used to measure HRQoL among 8–18 year-olds. Despite its effectiveness, concerns about its content validity persist, particularly in Chinese populations. This study evaluates the EQ-5D-Y’s content validity in China, focusing on the comprehensiveness, relevance, and comprehensibility of its dimensions among both healthy and diseased children.</p> Methods <p>A qualitative study was conducted with 30 participants (15 healthy, 15 diseased) aged 8–18 in Shanghai, China. The interviews explored participants’ perspectives on the EQ-5D-Y’s five dimensions, guided by the World Health Organization’s (WHO) definition of health. Data were analyzed using a framework approach, with response challenges identified through an adapted model of response issues.</p> Results <p>A total of 126 codes were generated, with 87 retained and categorized into three themes: physical (<i>n</i> = 16), mental (<i>n</i> = 30), and social health (<i>n</i> = 4). While responses reflected all five EQ-5D-Y dimensions, social health was notably mentioned as crucial but was absent in the EQ-5D-Y. Participants suggested enhancements in mental health coverage and more specific examples for the current dimensions.</p> Conclusion <p>The EQ-5D-Y is relevant for assessing HRQoL in Chinese children and adolescents but requires improvements, especially in incorporating social health. Enhancing question clarity and specificity could also improve its effectiveness. These findings guide potential refinements to better capture the health experiences of children.</p>