Many iterations of community based learning employ models, such as consciousness raising groups, cultural circles, and participatory action research. In all of them, learning is a deliberate part of an explicit educational activity. This article explores another realm of community learning: the informal learning that results from volunteering in community based organizations. This is a relevant issue, because millions of adults play an active role all over the world in improving their communities through volunteer organizations. When speaking to volunteers, one sees clearly that significant learning results from the unpaid work they engage in to improve their communities. In this article, the authors briefly put the concepts of informal learning and learning through volunteering into context. Then they explore three key areas in which volunteers learn: (1) instrumental skills related to their organization; (2) learning to work with others; and (3) learning about the role of volunteering in society. They hope that by highlighting the breadth and depth of volunteers' learning they can encourage individual volunteers, and organizations working with volunteers, to focus more attention on the learning dimensions of this type of civic engagement. This study of volunteers' informal learning is part of the Work and Lifelong Learning Network, which involved twelve case studies and a national survey of the Canadian adult population on informal learning more generally. The information presented in this article draws mainly on two of the authors' case studies, one with volunteers on housing cooperative committees and boards, and the other with volunteers in a variety of community based organizations.