Background: This study focused on an online education program based on Individual and Family Self-Management Theory. Purpose: The study investigated whether the education program affected adolescents' attitudes toward epilepsy, seizure self-efficacy, quality of life, and their parents' perceived nurse-support levels. Methods: The study is a single-blind, randomized, controlled trial. The study was conducted in the pediatric neurology outpatient clinic of a medical hospital between January 2021 and April 2022 in Konya. The sample consisted of adolescents with epilepsy (n = 36) and their parents (n = 36). The intervention group attended the education program in three main sessions, two weeks apart. The control group received routine education. Data were collected using a Child Demographics Form (CDF), a Parent Demographics Form (PDF), the Child Attitude Toward Illness Scale (CATIS), the Self-Efficacy Scale for Children with Epilepsy (SSES-C), the Pediatric Quality of Life Inventory (PedsQL), and the Nurse Parents Support Tool (NPST). The data were analyzed using descriptive statistics, Pearson's chi-square test, Fisher's Exact test, independent samples t-test, Mann-Whitney U test, Mixed design ANOVA analysis, Cohen's d, and 95 % confidence interval. This study adhered to CONSORT research guidelines. Results: The intervention group adolescents had a significantly higher mean of all scale scores than the control group adolescents. The intervention group parents had a significantly higher mean NPST score than the control group parents. Conclusion: Healthcare professionals should organize theory-based online education programs for adolescents and their parents at regular intervals for the self-management of epilepsy in special situations, such as pandemics, where face-to-face education is impossible. Practice implications: The study revealed that, unlike existing cues that highlight the effectiveness of face-to-face education, online interventions will strengthen epilepsy self-management of children with epilepsy and their parents. In extreme situations where face-to-face education has to be postponed for a long time and in routine education interventions, it is recommended to plan and implement online education so that children with chronic diseases can maintain their self-management. ClinicalTrials: The paper is registered in the Clinical Trials database (NCT04822662).