This community engagement program aims to strengthen community-based waste management in densely populated areas of Semarang City, Indonesia, as a practical model of community-driven environmental governance in the Global South while contributing to the achievement of the Sustainable Development Goals (SDGs), particularly SDG 11 (Sustainable Cities and Communities), SDG 12 (Responsible Consumption and Production), SDG 5 (Gender Equality), and SDG 17 (Partnerships for the Goals). The program adopted a Participatory Rural Appraisal (PRA) approach integrated with Indonesia's national legal framework, particularly the Regulation of the Minister of Environment and Forestry No. 14 of 2021 concerning Waste Banks, beginning with an assessment of the institutional, operational, financial, participatory, and regulatory conditions of existing waste banks to identify priority issues and capacity gaps. Based on these findings, two complementary interventions were implemented: capacity building for waste bank managers and community members, and technical-institutional strengthening. All participants were women, comprising waste bank managers and representatives of the Family Welfare Empowerment (PKK) organization, thereby highlighting the essential role of women in promoting gender-responsive environmental governance and community resilience. Post-training evaluation demonstrated significant improvements in participants' knowledge, awareness, and attitudes toward sustainable household waste management. Institutional strengthening was further supported through the development of a simple Excel-based management system, the preparation of standard operating procedures (SOPs) for operational and financial reporting, the provision of basic administrative facilities, and the establishment of a WhatsApp-based technical assistance service to ensure continuous mentoring. From a legal governance perspective, the program emphasized alignment between community waste management practices and national regulations while encouraging the adoption of complementary local legal instruments, including village decrees, environmental regulations, and partnership memoranda of understanding, to enhance transparency, accountability, and institutional sustainability. Overall, the findings demonstrate that integrating community empowerment, institutional capacity development, and legal compliance can significantly improve the governance and sustainability of community-based waste banks, offering a replicable and context-sensitive model for strengthening urban waste management in the Global South while supporting the realization of multiple SDG targets through inclusive, participatory, and sustainable environmental governance.