Social Enterprises face a significant challenge in improving their competitiveness without sacrificing their social objectives. Using an action research approach, we examine how the lean management tool 5S can be modified to fit the characteristics of the vulnerable workers involved in their operational processes. While 5S is typically applied to achieve efficiency, we find that the most important benefits of implementation for social enterprises are improvements in self-efficacy, ownership, and responsibility of the vulnerable workers. Other benefits were increased reliance on visual cues and reduced search time. Implementation of 5S highlighted the negative impact of circularity practices on operational efficiency.