Background: Comprehensive outcome measurement in pediatric palliative care focusing on the entire unit of care, that is, the affected child and its family, is crucial to depict treatment effects. Despite its increasing relevance, no appropriate multidimensional outcome measures exist for the largest patient group in this field, namely children with severe neurological impairments. Aim: The aim of this study was to develop and validate a family-centered multidimensional outcome measure for pediatric palliative care patients with severe neurological impairment that encompasses the entire unit of care. Design: Based on results of a qualitative study, the questionnaire was developed by consensus-based generation of questions. It was validated in a multicenter prospective study employing exploratory and confirmatory factor analyses as well as reliability and item analyses. Setting: A total of 11 pediatric palliative care teams across Germany aided in the recruitment of study participants. Questionnaires were answered by 149 parents of children with severe neurological impairment and 157 professional caregivers. Results: The exploratory factor analysis of parent data revealed a 6-factor structure of the questionnaire representing: symptoms, the child's social participation, normalcy, social support, coping with the disease and caregiver's competencies. This structure was verified by a confirmatory factor analysis of professional caregiver data. Five separate items regarding siblings, partners, and further symptoms not applicable for all patients were added to ensure full multidimensionality. Conclusion: A validated outcome tool for severely neurologically impaired pediatric palliative care patients, the FACETS-OF-PPC, now exists. Due to its concise length and appropriate psychometric properties, it is well suited for clinical application.