Adolescents and young adults (AYA) with cancer have been designated as a vulnerable population by the National Cancer Institute. This group, defined by the ages of 16-39 years, has not enjoyed the same survival improvements over the past several decades as older and younger cohorts. Several barriers prevent the optimal delivery of oncologic care in this subpopulation. This review will describe these challenges in the context of the major hematologic malignancies affecting this population (acute lymphoblastic leukemia ALL, acute myeloid leukemia AML, Hodgkin lymphoma HL, and non-Hodgkin lymphoma NHL). For example, historical differences in care delivery between pediatric and adult health care systems have created confusion about optimal treatment planning for AYAs, a population that spans the pediatric-adult divide. In the case of ALL, retrospective studies have demonstrated significantly better outcomes when AYAs are treated according to pediatric and not adult protocols. Additional challenges more specific to AYAs include increased treatment-related toxicity relative to younger patients; less access to care and, specifically, access to clinical trials; lower adherence to medications and treatment plans; and psychosocial stressors relevant to individuals at this stage of life. Recognizing and responding to these challenges in AYAs may create opportunities to improve the cancer outcomes of this group.