<p>The growing demand for sustainable energy solutions is driving the search for renewable alternatives to fossil fuels, particularly in developing countries such as Angola. In this context, the present study provides a comprehensive review of the conversion of waste cooking oil (WCO) into biodiesel, examining its potential in light of the principles of the circular economy. The main objective was to evaluate the environmental and operational benefits of this approach within the Angolan context. The adopted methodology involved a broad and systematic review of recent scientific literature, focusing on transesterification processes, conversion efficiency, the properties of the resulting biodiesel, and the environmental impacts associated with its production and use. The results indicate that biodiesel derived from WCO leads to significant reductions in atmospheric pollutants and greenhouse gas emissions when compared to conventional fossil diesel. Additionally, it contributes to improved urban waste management practices. The valorization of WCO as a feedstock promotes environmental, economic, and social benefits, while also strengthening local value chains and creating job opportunities. Thus, the integration of circular economy principles into biodiesel production emerges as a feasible and promising pathway for diversifying Angola’s energy matrix. Future studies should focus on optimizing WCO collection logistics, enabling large-scale production facilities, and conducting comprehensive life-cycle assessments to accurately quantify the long-term environmental and economic benefits arising from the use of innovative technologies.</p>