Background: Juvenile diabetes is the most common endocrine disease during infancy and adolescence causing serious coping problems so adolescents must adapt to and effectively manage their illness. Aim: this study aimed to assess the self-efficacy among adolescents with juvenile diabetes. The disease is characterized by extremely limited or nonexistent insulin secretion. Clinically apparent diabetes with hyperglycemia or ketoacidosis manifests only when at least 90% of the insulin-secreting cells have been eliminated and insulin deprivation becomes severe. Pediatric nurses play an important role in the early detection of diabetes and are able to intervene and manage the condition early on. The majority of nurses have a specialist qualification in providing diabetes special education and support for adolescents in treatment decisions regarding their illness Design: A descriptive research design was utilized in the current study. Setting: This study was conducted at outpatient pediatric endocrinology clinic at Beni Suef university Hospital. Subjects: A purposive sample of 84 adolescents with juvenile diabetes attending the previously mentioned study setting. Tools of data collection: Three tools were used to collect data: tool (1) interviewing questionnaire: (2) checklist of reported practices, tool (3) self-efficacy scale to assess self-efficacy among adolescents with juvenile diabetes. Results: more than half of the studied adolescents had unsatisfactory total knowledge level about juvenile diabetes, more than two thirds of them had incomplete reported practices and nearly two thirds of them had a low selfefficacy score. Conclusion: Adolescents with juvenile diabetes had unsatisfactory total knowledge score and incomplete total reported practices. In addition to, most of them had a low self-efficacy score. Recommendation: Establishing educational programs to improve self-efficacy of the adolescents with juvenile diabetes.