The aim of this study was to assess the agreement between deaf children's and adolescents' self-ratings of health-related quality of life (HRQoL) and their parents' proxy reports. This observational cross-sectional study included 114 deaf 8- to 18-years-old students and proxy family members. HRQoL was measured using the KIDSCREEN-27 questionnaire, which was adapted to Spanish sign language for children, with a written version for parents. Respondents completed a self-administered paper questionnaire. Parents' and children's mean scores differences were not significant, except for the "Autonomy and Parents" and "Peers and Social Support" dimensions. Children aged 8-11 years scored higher in some domains of QoL compared to those aged 12-18 years. The level of agreement between children/adolescents' and parents/proxies' responses was acceptable, except for the dimension "Autonomy and Parents." Overall, deaf children/adolescents' self-ratings of HRQoL did not differ from their parents' proxy reports; however, differences were found in the dimensions that explored the quality of the interaction of children/adolescents and parents, the perceived level of autonomy, and social relations and support.