Breast cancer is one of the leading causes of death among women worldwide, including in Indonesia. Breast self-examination (BSE) is an important early detection effort that should be practiced from adolescence. Preliminary surveys at State Senior High School 4 Bengkulu City revealed that most female students had neither knowledge of nor experience in performing BSE. Therefore, this study aims to determine the effect of peer educator empowerment on improving the knowledge and skills of adolescent girls regarding BSE at State Senior High School 4 Bengkulu City in 2025. This study employed a pre-experimental design with a one-group pretest–posttest approach. The sample consisted of 35 twelfth-grade female students, selected using proportional systematic sampling. The intervention was conducted through the empowerment of 35 peer educators who received training over three sessions, after which they provided education on breast cancer and the procedure for performing BSE to their peers. Data were collected using a knowledge questionnaire and a skills checklist, and analyzed using the Wilcoxon Signed Rank Test. The results showed a significant improvement in both knowledge and skills after the intervention. The average knowledge score increased from 7.09 to 16.54, while the skills score increased from 7.86 to 72.71. The Wilcoxon test revealed p-values of 0.000 for both knowledge and skills variables (<0.05), indicating a statistically significant effect. These findings demonstrate that peer educator empowerment significantly influences the improvement of knowledge and skills among adolescent girls regarding BSE at State Senior High School 4 Bengkulu City. It is recommended that State Senior High School 4 Bengkulu City reactivate its peer group program as a platform for health education, particularly concerning breast self-examination (BSE), and ensure the sustainability of such activities to be carried out regularly.

Breast Cancer, Peer Educator, Knowledge, Breast Self-examination (BSE), Skills, Adolescent Girls