BACKGROUND: This qualitative study investigated the medical decision-making preferences of adolescent oncology patients and the parental and clinician behaviors that adolescents report to be supportive of their preferred level of decision-making involvement. METHODS: Interviews were conducted with 40 adolescents between the ages of 12 and 18 years who were undergoing cancer treatment in Memphis, Tenn or Washington, DC. Role preferences were converted into a predetermined Likert scale decisional preference score. A semantic content analysis was used to analyze patient reports of parental behaviors, attitudes, knowledge levels, and relational interactions that facilitated their preferred level of involvement in decision making. Clinician behaviors described as supportive of decisional processes were also categorized thematically. A teen advisory council validated study findings. Data reporting followed strict adherence to Consolidated Criteria for Reporting Qualitative Research guidelines. RESULTS: Adolescents indicated a spectrum of preferred decisional roles, with the most common being an actively involved role (26 of 40 or 65%), although a shared decisionmaking approach was still valued. There was no statistically significant difference in the preferred decisional role with respect to demographic or medical characteristics, including the relapse status, although adolescents who preferred autonomous interview settings were more likely to prefer active decisional roles (P <.001). Adolescents recognized that situational and social contexts might shift their preferred level of involvement in medical decisions. Although adolescents wanted to be involved in decisions, they also expressed an appreciation of family insight, parental presence, and clinician guidance. CONCLUSIONS: Adolescents with cancer are able to retrospectively identify their preferences for inclusion in medical decision making, and even when preferring involvement, they value the input of trusted others. Cancer 2015;121:4416-24.