Group supervision was introduced as a quality improvement intervention to improve the performance of Health Extension Workers (HEWs) providing maternal health services in Sidama Zone, Ethiopia. The intervention included training supervisors and implementing monthly group meetings where HEWs discussed collected data, problems, and solutions. Results showed the intervention improved HEW motivation and regularity of supervision meetings. Utilization of maternal health services increased, including antenatal care attendance and skilled delivery rates. However, challenges included lack of transportation support for supervisors and high supervisor turnover. Overall, the findings demonstrated that group supervision can positively impact HEW performance and maternal health outcomes.