Recent years have seen increased emphasis on the idea of schools working together. However, there is very little research that demonstrates how and when such approaches lead to positive outcomes, particularly in respect to those schools facing challenging circumstances. Reflecting on the evidence from six case studies, this article identifies strategies that offer pointers for the development of practice and indications of where further research is needed. It concludes that, under the right circumstances, school-to-school collaboration is a powerful means of strengthening the capacity of schools to address the challenges they face. More specifically, it suggests that collaboration can: widen student learning opportunities and help address the needs of vulnerable groups of learners; be effective in helping schools to resolve immediate problems; and, under certain conditions, contribute to the raising of expectations.