Purpose: This study aims to explore co-learning classes, a novel approach to leveraging universities' capacity to contribute to the local sustainable development agenda whilst enhancing students' learning. These participatory classes were piloted within a UK university masters' module focussed on action for sustainability. The classes sought to combine knowledge exchange, reflection and social network development by bringing together students and community stakeholders. Design/methodology/approach: The classes were run as a series of five free events, each focussed on sustainability issues relevant for local practitioners. These were either regular timetabled sessions opened up to the public or additional on-campus public events. Attendance was either face-to-face or online. Evaluation was based upon participation data, written feedback and module leader's post-event reflections. Findings: The classes successfully secured participation from diverse community members, including local government staff, voluntary sector workers and interested individuals. Both students and community stakeholders valued the participatory format, linkages of theoretical and practical knowledge and diversity of attendees. Research limitations/implications: Findings are based upon a small-scale pilot study. Further research using a wider range of contexts is required to enhance understanding of the co-learning approach. Practical implications: This paper highlights some key practical issues to consider if employing co-learning approaches in other contexts, including using inclusive language, aligning with students' motivations and choosing appropriate focal event topics. Originality/value: Opening up participatory university classes for the public to attend as co-learners is a rarely used approach and has little coverage in academic literature. This small-scale study therefore has value by highlighting some of the potential impacts, strengths and limitations of this approach.