A shift in how to measure well-being using more appropriate and coherent indicators has been long called for. Nonetheless, monetary indicators, such as income and GDP, or utilitarian frameworks, remain the most common approaches used. The capability approach (CA) has been advocated as an alternative framework to measure well-being. This paper aims to capture the state-of-the-art of how the CA has been applied to assess or characterise the well-being impacts of project-based development interventions in Global South countries. The ultimate goal is to discuss whether the CA provides more varied and complex indicators of well-being and therefore more comprehensive impact assessments. The results highlight that qualitative and participatory approaches are frequently applied methods to assess individual capabilities, most often related to educational, economic, social and empowerment dimensions. Capabilities linked to environmental and recreational activities, as well as collective capabilities, were significantly overlooked. Quantitative approaches to impact evaluation were less frequently used. This paper provides a first systematic review on the use of the CA to assess well-being impacts. Future applications of the CA could focus on better integration of qualitative and quantitative approaches for robust impact assessments and targeting understudied capabilities.