Perceived support and conflict between adolescents and young adults with cancer and their primary caregivers, other family, close friends, and medical staff were examined in relation to adolescents and young adults' psychological health. Adolescents and young adults ( n = 115, 51% male, ages 12-24 years, M (standard deviation) = 16.07 (2.29)) in outpatient cancer treatment perceived more support and conflict within familial relationships than other relationships. Among familial relationships, perceived support and conflict were associated with psychological health; within other relationships, only support was associated with psychological health. Interactions among family were most strongly correlated with psychological distress; interactions with friends were stronger correlates of posttraumatic stress symptoms, positive affect, and posttraumatic growth.