<p>Semi-arid cities in the borderlands of the southwestern United States of America are becoming critical frontiers in the socio-ecological challenges emerging at the confluence of climate change, social justice, and sustainable development. While the emerging literature emphasizes the potential role of circular food systems, there has been little scholarly and policy attention to circular food-oriented Community-based Organizations (CBOs) in medium-sized semi-arid cities experiencing intense drought and growing social inequalities. Using an exploratory qualitative design, this paper examined the circular food practices of three major CBOs in Tucson, Arizona. Through in-depth interviews with staff and volunteers and on-site observations, the study found that circular food practices in Tucson are implemented to address social, environmental, and economic challenges facing marginalized populations. Our paper illuminates how localizing circular food systems generates co-benefits that support sustainable development by reducing food waste, reusing excess products, and repurposing by-products. This paper provides new insights for environmental policymakers and planners to support the development of synergies and linkages among CBOs, enhance resource capacity, and integrate circular food practices to foster equity-focused sustainable development of semi-arid cities confronted with socio-ecological stressors.</p>