Children with meningomyelocele may require continuous care. Consequently, there is a risk for caregiver burden and impact on family quality of life (QoL), including siblings' QoL. Some studies analysed caregivers' burden and family QoL separately. However, none of these studies evaluated siblings' QoL and the associations between these three dimensions. This study investigated the associations between caregivers' burden, family QoL and siblings' QoL in Brazilian families of children with meningomyelocele and its correlations with sociodemographic, functional and clinical variables. Siblings' QoL was specifically assessed using as a parameter the QoL of typically developed Brazilian children. One hundred and fifty families, 150 caregivers and 68 siblings completed the Family Quality of Life Scale, Burden Interview, KIDSCREEN-27 Child and Adolescent Version and Parents Version questionnaires. Most families and caregivers reported a high family QoL and a low caregiver burden. Family QoL was significantly lower as caregivers' burden increased. Caregiver's burden was significantly lower with increasing family QoL levels. Self-reported siblings' QoL was significantly worse than that of typically developed peers. There were no significant differences between self and parent-reported siblings' QoL. Self-reported siblings' QoL was significantly worse as their age increased and better with increasing family QoL levels. Parent-reported siblings' QoL was significantly worse with increasing levels of caregiver's burden and significantly better as family QoL increased. There were no significant associations with functional and clinical variables. Despite the cross-sectional nature of the available data precludes any statements of causality, our results reinforce the relevance of knowing the factors that influence the QoL of families and siblings of children and adolescents with meningomyelocele and the relevance of actions aimed at reducing caregivers' burden, improving family QoL and meeting siblings' individual needs. Future multicenter studies may validate the generalizability of our findings.