Background <p>Type 1 diabetes is a common chronic disease in adolescents, requiring continuous self-care and attention to quality of life. With the rise of digital health technologies, eHealth literacy may play a key role in promoting self-care behaviors and well-being. This study aimed to investigate the relationships between eHealth literacy, self-care behaviors, and quality of life in adolescents with type 1 diabetes.</p> Methods <p>In this descriptive-analytical cross-sectional study, 250 adolescents with type 1 diabetes completed validated questionnaires assessing Electronic Health Literacy (eHEALS), diabetes-specific self-care behaviors (SMOD-A), and health-related quality of life (Diabetes Quality of Life for Youth [DQOLY]). Data were analyzed using descriptive statistics, Spearman’s correlation, and multiple linear regression.</p> Results <p>Participants (mean age = 14.36 years; 54.8% male) mostly had low eHealth literacy (81.2%). eHealth literacy correlated positively with self-care (<i>r</i> = 0.43) and quality of life (<i>r</i> = 0.36), while self-care was strongly related to quality of life (<i>r</i> = 0.51; <i>p</i> &lt; 0.01). Regression models explained 35% of the variance in self-care and 29% in quality of life. Mediation analysis confirmed a significant indirect effect of eHealth literacy on quality of life through self-care behaviors (β = 0.219, <i>p</i> &lt; 0.05).</p> Conclusions <p>Enhancing eHealth literacy plays a key role in improving self-care behaviors among adolescents with type 1 diabetes, which is directly associated with better quality of life. The findings of this study clearly highlight the importance of promoting eHealth literacy as an essential component of targeted, technology-based educational interventions to improve diabetes management in this age group.</p>