Background <p>Adolescent and young adult (AYA) cancer survivors (ages 15–39 at diagnosis) experience challenges that heighten their risk of financial toxicity (i.e., the material, psychological, and behavioral burden of cancer-related costs). This scoping review characterizes the extent, range, and limitations of the literature on financial toxicity among AYA cancer survivors to inform future research and intervention design.</p> Methods <p>Following standardized scoping review methodology, we systematically searched six databases for studies addressing financial toxicity or related constructs among AYAs within the past 10&#xa0;years. Eligible studies included quantitative, qualitative, and mixed-methods research without geographic restriction. Of 1722 records identified, 1362 underwent title and abstract screening and 118 underwent full-text review. Two reviewers independently screened studies, and study data were extracted and synthesized.</p> Results <p>Eighty studies met inclusion criteria. Most (<i>n</i> = 74, 92%) were cross-sectional, six (8%) were longitudinal. Half (<i>n</i> = 40, 50%) were quantitative observational analyses, and 41 (51%) included multiple cancer types. Financial toxicity was measured as an outcome in 63 studies (79%) and an exposure in 17 (21%). Prevalence of financial toxicity ranged from 15.5% to 89.5% (median 55%, IQR 38.2–67.1). Considerable heterogeneity was observed in measurement approaches; the Comprehensive Score for Financial Toxicity (COST) measure was used in 22 studies.</p> Conclusions <p>Standardized measurement, longitudinal designs, and multilevel interventions are needed to mitigate burden and advance health equity.</p> Implications for Cancer Survivors <p>Financial toxicity is a pervasive concern for AYA cancer survivors globally. Through synthesizing the existing evidence on financial toxicity among AYA cancer survivors, this review identifies key gaps and guides future research and intervention development.</p>