<p>Rapid urbanization in Sub-Saharan Africa has intensified challenges in solid waste management (SWM), necessitating innovative and integrative approaches, such as the circular economy (CE), to achieve sustainability goals. This study examines the socio-ecological dimensions of the Circular Economy–Solid Waste–Sustainability Education nexus in Addis Ababa, Ethiopia, where high waste generation, service gaps in municipal services, and informal recycling coexist. Employing a mixed-methods design, quantitative household surveys were complemented with semi-structured interviews and focus group discussions to capture both numerical patterns and socio-cultural contexts. The study reveals that although national policies support CE implementation and encourage active community participation in waste collection through micro and small enterprises (MSEs), practical challenges persist—including limited access to recycling markets, weak institutional coordination, and insufficient sustainability education and public awareness. Statistical analysis indicates a significant relationship between CE knowledge and improved household waste sorting behavior (<i>p</i> &lt; 0.05). Notably, 90% of respondents expressed a desire for further CE and environmental education, preferring local media and community-based outreach. These findings underscore the importance of embedding sustainability education and socio-ecological learning into urban waste governance. Strengthening the CE–SWM nexus through institutional support for MSEs, participatory education, and public–private partnerships is essential to foster a more inclusive, circular, and sustainable waste system aligned with SDG 11 and Ethiopia’s Green Urbanization agenda.</p>