Quality measures have been devised for end-of-life care of older adults with cancer, but are lacking for adolescents and young adults (AYAs). We previously conducted interviews with AYAs, family caregivers, and clinicians to identify priority domains for high quality care of AYAs with advanced cancer. The goal of this study was to use a modified Delphi process to form consensus around the highest priority quality indicators. A modified Delphi process was conducted with 10 AYAs with recurrent or metastatic cancer, 11 family caregivers, and 29 multidisciplinary clinicians, using small group web conferences. Participants were asked to rate the importance of each of 41 potential quality indicators, rank the 10 most important, and engage in discussion to reconcile differences. Of 41 initial indicators, 34 were rated as highly important (rating 7, 8, or 9 on a 9-point scale) by >70% of participants. The panel was unable to reach consensus around the 10 most important indicators. Instead, participants recommended retaining a larger set of indicators to reflect potential for different priorities across the population, resulting in a final set of 32 indicators. Recommended indicators broadly encompassed attention to physical symptoms; quality of life; psychosocial and spiritual care; communication and decision-making; relationships with clinicians; care and treatment; and independence. A patient- and family-centered process for quality indicator development led to strong endorsement of multiple potential indicators by Delphi participants. Further validation and refinement will be performed using a survey of bereaved family members.