Maternal and neonatal mortality remain critical public health challenges in Indonesia, particularly within decentralized health systems where early detection, referral coordination, and continuity of care are often fragmented. This study aimed to evaluate the implementation and outcomes of a district-level Quality Improvement (QI) Collaborative designed to strengthen maternal and neonatal services and reduce major obstetric and neonatal complications in Jember Regency, Indonesia. A quasi-experimental implementation study was conducted using aggregated routine data from primary healthcare centers and referral hospitals. The QI Collaborative was implemented in two phases from December 2023 to April 2025, focusing on standardized risk screening, early clinical recognition, strengthened referral pathways, and district-level supervision. Trends in postpartum hemorrhage, preeclampsia/eclampsia, and neonatal asphyxia were analyzed using run charts and median-based trend analysis. The findings demonstrated improved adherence to standardized screening and referral protocols, indicating strengthened district clinical governance. Reductions below baseline medians were observed for postpartum hemorrhage and neonatal asphyxia. An initial increase in preeclampsia/eclampsia cases reflected improved detection, followed by declining trends as supervision and service integration improved. This study provides empirical evidence that district-level QI Collaboratives can enhance service performance and clinical governance, offering a scalable model to strengthen decentralized maternal and neonatal health systems in low- and middle-income settings.