Background Pediatric traumatic brain injury (TBI) may cause a wide range of symptoms, which can negatively affect the quality of life of patients and their entire families. No internationally and simultaneously developed disease-specific instrument exists for assessing pediatric health-related quality of life (HRQoL) after TBI. The aim of the current project is to provide original material from small group interviews with individuals after TBI concerning what they state is relevant for their HRQoL. This material is required for a further study to generate items for age-adapted questionnaires assessing the TBI-specific HRQoL of children and adolescents (C&A): the QOLIBRI-Kiddy/Kid/Ado and proxy versions (Quality of Life after Brain Injury-Kiddy/Kids/Adolescents/Proxy) for individuals aged 6-17 and their parents. Methods The semi-structured interviews were conducted with separate small groups of C&A (n = 19), divided into three age groups (5-7y, 8-12y, 13-17y), after mild, moderate, and severe TBI, and with groups of the corresponding parents (n = 26). All interviews lasted for about 60 minutes, were recorded and transcribed verbatim. The statements were investigated by qualitative analyses and sorted into categories relevant to the HRQoL of C&A after TBI. Only descriptive group comparisons but no pairwise comparisons between children and corresponding parents were performed. Results The analyses led to 32 subcategories, which were assigned to six main theoretically based HRQoL categories. Many agreements exist between the C&A's and parents' perspectives within the main categories, however their focus on HRQoL differs, especially concerning age-related contents. Parents of the youngest participant group already focus on topics such as autonomy, whereas this only becomes relevant for C&A from the age of eight years on. Interestingly, even 5-year-old children were able to discuss their HRQoL, which indicates the importance of a self-report instrument. Conclusions Results obtained from this qualitative study identify the content of the HRQoL dimensions important for C&A after TBI and their parents. Both, differences and similarities in the children's and the parents' views were investigated, to get a first insight in valid dimensions for the prospective questionnaires to be developed. In a future study, items for the questionnaires will be deducted from the small group interview material and psychometrically tested in C&A after TBI from Germany. This study will address whether all statements were assigned to the suitable dimensions and whether differences between C&A and parents persist.