Background: National Quality Forum (NQF)-endorsed end-of-life (EOL) quality measures helped identify disparities in quality of EOL care in adults with cancer. In adults, those quality measures apply to all adults dying with cancer or those with Stage III or IV disease. Quality measures for EOL care for children with cancer were recently developed. However, identifying the denominator for EOL quality measures in children with cancer is more nuanced than in adults. Therefore, we utilized the Nominal Group Technique to determine to whom these EOL quality measures should be applied (i.e., the denominator). Methods: In a series of Nominal Groups, panelists answered the question: "Which children, diagnoses, conditions, or prognoses should be included when examining the quality of EOL care for children with cancer?" In each group, individuals first proposed answers to the group and then selected the 5 options they thought best answered the question. Five points were assigned to the statement that was the best answer, 4 the second best, etc. A team developed a framework of themes and subthemes based on the responses and coded each statement, with multiple meetings to develop consensus. Results: We conducted 5 separate Nominal Groups with a total of 44 participants. Most identified as female (88%) and Non-Hispanic White (86%). Seventy-nine percent were pediatric palliative care, pediatric oncology, pediatric critical care, or hospice clinicians, 40% researchers, and 12% bereaved parents. Responses fell into 5 themes: (1) Poor prognosis cancer (e.g. a child with a relapsed or refractory cancer); (2) Specific treatment scenarios (e.g. children who have no further curative treatment options available); (3) Certain populations (e.g.all adolescent and young adult patients); (4) Certain symptoms (e.g. respiratory depression related to brain malignancy); (5) Specific utilization scenarios (patients requiring two or more life-sustaining therapies). Poor prognosis cancer and specific treatment scenarios received the most points (320 points [49%] and 146.5 points [23%], respectively). Conclusions: Interprofessional Nominal Group participants created a framework for identifying children who should be included in EOL quality measures for children with cancer. This differs from similar work in adults in that it does not include all children with cancer or limit to patients with advanced disease. This framework will be a powerful tool for quality improvement, research, and clinical program development and is a critically important step to ensure all children with cancer receive high-quality EOL care.