Li-Fraumeni syndrome (LFS) is a highly penetrant cancer predisposition syndrome that may present with a first cancer before or during adolescence/young adulthood. Families offered LFS genetic testing for their children can inform our understanding of how the unique developmental context of adolescence influences parental perspectives about genetic testing and discussions of cancer risk. In this study, semi-structured interviews were conducted with 46 parents of children at risk for LFS to capture those perspectives. Analysis utilized summary descriptive statistics and inductive qualitative content coding. Most parents (33/46; 72%) expressed beliefs that adolescence influences the importance of LFS testing and/or discussions about genetic risk. Twenty-six parents related this influence to cognitive, physical, and social changes occurring during adolescence. Aspects of adolescence perceived as promoting LFS testing/discussion included developmental appropriateness, risks of cancer in adolescence, need for medical screening decisions, influence on behaviors, transition to adult health care, and reproductive risks. Aspects of adolescence perceived as complicating LFS testing/discussions included potential negative emotional impact, misunderstanding, added burden, and negative impact on self-image or future planning. Parents recognize the complex influence that adolescence has on LFS testing and conversations surrounding results. Further research is needed to understand the actual impact of genetic testing on young people, and how to best support parents and adolescents within the broader context of heritable diseases.