This study examined the financial impact of cancer and the use of income support in adolescents and young adults (AYAs) with cancer and their parent caregivers. As part of a national Australian study exploring the psychosocial impacts of cancer, 196 AYAs ages 15 to 25 years, six to 24 months from diagnosis, and 204 parent caregivers from 18 cancer sites were surveyed. Logistic regression and chi-square analyses were conducted to assess the influence of clinical and sociodemographic variables on financial status. Qualitative responses were coded, and key themes were identified using thematic analysis. The findings indicate that more than half of AYAs and parents reported financial issues as a consequence of AYA cancer. Financial issues resulted from direct medical costs, associated costs from treatment, and indirect costs from loss of income. AYAs and parents reported that it was important for them to receive income support, both during and after cancer treatment. However, large proportions of those who reported needing income support had difficulty accessing it. AYAs and their families are substantially financially disadvantaged by cancer, many for a prolonged time. Patient- and family-centered assessments and interventions are required to reduce the financial burden of AYA cancer.