PURPOSE: Retinoblastoma is an aggressive pediatric eye cancer. Patient-reported outcome measures reveal important insights into how patients perceive their own health. Currently, there is no widely used or validated measure for assessment of retinoblastoma outcomes. The purpose of this research was to uncover which treatment outcomes that retinoblastoma survivors and their parents value, to inform the development of a future measure. METHODS: This qualitative, cross-sectional study included retinoblastoma survivors age 6 years and older and parents of retinoblastoma survivors. Participants who did not demonstrate fluency in English were excluded. Study participants participated in semistructured interviews or focus groups, either in person at The Hospital for Sick Children, Toronto, Canada, or through secure videoconference, between March 3, 2019, and January 25, 2020. Iterative rounds of opening coding, codebook development, and coresearcher analysis were used to identify key emergent themes and subthemes. RESULTS: Seventeen adults participated in six focus groups. Nine pediatric survivors participated in individual interviews. Four common themes emerged from all participant groups: (1) definition of treatment success, (2) enucleation—acceptance and challenges, (3) treatment outcomes to measure, and (4) need for outcome reporting. An additional, unique theme was identified in all pediatric discussions: worries and coping mechanisms. Treatment outcomes deemed valuable were related to the following domains: psychosocial outcomes, daily functioning, functional vision, retinoblastoma education, cosmetic outcomes, and secondary eye conditions. CONCLUSION: This study represents the first stage in the development of a retinoblastoma-specific patient-reported outcome measure. The findings reveal insight into what outcomes are valued by survivors after treatment and offer promise to improve outcomes assessment for retinoblastoma.