Trusts and foundations are increasingly looking to become agents of social change themselves as well as funders of it—asking themselves whether providing more than direct services might make more of a difference. Two common ways that funders do this are through providing support to help organisations develop their capacity, and by using a funder’s influence to advocate for change. Here we focus on the former, looking at organisational development support provided by funders from around the world—exploring the types of support given, the evidence for whether it works, and how funders can approach impact measurement.