The article examines the strategies by which environmentally-motivated social enterprises seek to scale up their positive impacts, drawing on a theoretical understanding of the role of entrepreneurial agency in transitions to a more sustainable economy and society. Case study evidence is used to explore different forms of enterprise growth, contributions to economic, environmental and social value, and the capabilities involved in their realisation. A typology of three distinct approaches or modes is introduced to help explain orientations and strategies that reflect both conventional conceptions of growth and alternative ways of growing social and environmental value. The role of values, capabilities and relational learning in shaping strategies and addressing the tensions and challenges encountered within each category is highlighted.