The financial impact of cancer treatment among adolescents and young adults (AYAs, 15–39 years) is deep and long lasting. Compared with other age groups, because of their life stage, AYAs are particularly vulnerable to the adverse economic effects of cancer treatment, also known as financial toxicity. Clinical manifestations of cancer‐related financial toxicity include interrupted work and income loss, accumulated debt, treatment nonadherence, avoidance of medical care, and social isolation. Effective clinical interventions should include efforts to increase financial self‐efficacy as well as direct support. Measures that are valid, reliable, multidimensional, and age‐appropriate are needed to study and address financial toxicity in the AYA population.