The aims of this study were to: a) determine if self-efficacy mediates the relationship between perceived stress and diabetes self-management in adolescents with type 1 diabetes; and b) explore whether perceived stress moderated the self-efficacy and diabetes self-management relationship.Non-experimental, descriptive correlational design, conducted from January- December 2016.Guided by the Adaptation to Diabetes framework, data on demographic and clinical characteristics, perceived stress, self-efficacy and diabetes self-management were collected. Descriptive analyses and regression analyses were generated by SPSS Version 22. Structural equation modeling was implemented with the MPlus program.There was no direct effect of perceived stress on diabetes self-management; however, self-efficacy mediated the relationship between perceived stress and diabetes self-management. Adolescents who had high self-efficacy and low perceived stress demonstrated better diabetes care activities and diabetes communication than would be predicted from the main effects of self-efficacy and perceived stress alone.Decreasing perceived stress and improving self-efficacy are important strategies to improve diabetes self-management in adolescents with type 1 diabetes.Adolescents with type 1 diabetes experience considerable stress with daily self-management demands. This study highlights the mediating role of self-efficacy on perceived stress and diabetes self-management. Assessment of perceived stress and self-efficacy in self-management tasks in adolescents with T1D may help nurses individualize self-management education and support. Incorporating strategies to promote stress management and self-efficacy in diabetes education may also improve diabetes self-management. This article is protected by copyright. All rights reserved.