Objective: Decreased health-related quality of life (HRQOL) in pediatric patients with multiple sclerosis is established, but little research has examined HRQOL in the broader pediatric demyelinating disease population, and predictors of reduced HRQOL are largely unexplored. We sought to (1) compare generic HRQOL and fatigue of pediatric patients with relapsing (i.e., multiple sclerosis and neuromyelitis optica) versus monophasic demyelinating diseases (i.e., acute disseminated encephalomyelitis, optic neuritis, transverse myelitis, clinically isolated syndrome) and (2) examine the extent to which disability, relapsing disease, and fatigue predict HRQOL. Methods: Child and/ or parent-proxy reports of generic and fatigue-related HRQOL were collected for 64 pediatric patients with demyelinating diseases. HRQOL of the sample was compared with published healthy child norms. Independent samples t-tests compared HRQOL and fatigue for children with monophasic versus relapsing diseases. Regression analyses examined disability, disease presentation, and fatigue as potential predictors of HRQOL. Results: Compared with healthy child norms, generic HRQOL was significantly lower for the demyelinating disorder group, for both child and parent reports across multiple domains. As hypothesized, the relapsing disease group reported lower overall HRQOL and more fatigue than the monophasic group. Disability and relapsing disease predicted lower HRQOL for both parents and children, whereas fatigue was only predictive per the child perspective. Conclusions: Children with demyelinating diseases evidence significantly lower HRQOL than healthy peers, supporting need for intervention. Those with relapsing disease appear particularly at risk; targeting disability and fatigue may be fruitful areas for intervention.