Physical activity is increasingly being studied as a way to improve psychosocial outcomes (e.g., quality of life, self-efficacy, physical self-perceptions, self-esteem, body image, posttraumatic growth) among survivors of adolescent and young adult (AYA) cancer. Assessing levels of and associations between self-reported physical activity and psychosocial outcomes requires clear, appropriate, and relevant questionnaires. To explore how survivors of AYA cancer interpreted and responded to the following eight published questionnaires: Leisure Time Exercise Questionnaire, Exercise Self-Efficacy Scale, Physical Self-Description Questionnaire, Rosenberg Global Self-Esteem Scale, Multidimensional Body-Self Relations Questionnaire, Posttraumatic Growth Inventory, Functional Assessment of Cancer Therapy-General (FACT-G), RAND 36-Item Health Survey 1.0 (RAND-36), cognitive interviews were conducted with three men and four women age 18-36 years who were diagnosed with cancer at age 16-35 years. Initially, the first seven questionnaires listed above were assessed. Summaries of the interviews were prepared and compared across participants. Potential concerns were identified with the FACT-G; thus, a second interview was conducted with participants to explore the clarity, appropriateness, and relevance of the RAND-36. Concerns identified for the FACT-G related mostly to the lack of relevance of items pertaining to cancer-specific aspects of quality of life given that participants were posttreatment. No or few concerns related to comprehension and/or structure/logic were identified for the other questionnaires. In general, the questionnaires assessed were clear, appropriate, and relevant. Participants' feedback suggested they could be used to assess self-reported physical activity and varied psychosocial outcomes in studies with survivors of AYA cancer, either with or without slight modifications.