The National Cancer Institute developed the Family Life, Activity, Sun, Health, and Eating (FLASHE) Study to examine multiple cancer preventive behaviors within parent–adolescent dyads. The purpose of creating FLASHE was to enable the examination of physical activity, diet, and other cancer preventive behaviors and potential correlates among parent–adolescent dyads. FLASHE surveys were developed from a process involving: literature reviews, scientific input from experts in the field, cognitive testing, and usability testing. This cross-sectional, web-based study of parents and their adolescent children (aged 12–17 years) was administered between April and October 2014. The nationwide sample consisted of 1,573 parent–adolescent dyads (1,699 parents and 1,581 adolescents) who returned all FLASHE surveys. FLASHE assessed parent and adolescent reports of several intrapersonal and interpersonal domains (including psychosocial variables, parenting, and the community and home environments). On a subset of example FLASHE items across these domains, responses of parents and adolescents within the same dyads were positively and significantly correlated (r =0.32–0.63). Analyses were run in 2015–2016. FLASHE data present multiple opportunities for studying research questions among individuals or dyads, including the ability to examine similarity between parents and adolescents on many constructs relevant to cancer preventive behaviors. FLASHE data are publicly available for researchers and practitioners to help advance research on cancer preventive health behaviors.