A high incidence of injuries has been reported in young athletes. Several factors have been associated with athletes’ sports injuries. However, scientific evidence is lacking, particularly for adolescent athletes. Hence, the Healthy Injury-Free Adolescent Athletes (HIFAA) was designed to evaluate sports injuries and examine associations with risk factors related to physical load and mental health. Secondary aims are to evaluate differences between sex, age, high school year and sports and examine injuries and the athletic situation 5 to 10 years after graduation. Adolescent athletes aged 15–19 years enrolled in high school and competing in sports to reach a national or international level of sports will be included. At inclusion, athletes will sign an informed consent form and fill out a baseline questionnaire addressing potential risk factors (eg, sports, training and competing health and injuries, and psychosocial status). Athletes will then prospectively be monitored weekly regarding injuries, physical (training/match/competing, perceived exertion) and psychological (fatigue, sleep, mental stress, recovery) load until graduation. A shortened version of the baseline questionnaire will be filled out every year, and a follow-up questionnaire regarding injuries, sporting situations and mental health will be filled out 5–10 years after graduation.Injuries are frequent among adolescent athletes, with consequences ranging from shorter interruptions in sports performance to mental health problems and early termination of sports. A reduction of these injuries is warranted. This study will provide a detailed understanding of risk factors, a prerequisite to introducing appropriate preventive measures.