This is a study about the motives, interests and capacities that lead both humanitarian and commercial organisations to work together in places affected by disaster or conflict. It considers how these different interests and motives affect the way the two sectors approach their engagement in humanitarian activities, jointly and separately, and the opportunities and challenges that their respective interests and practices pose to their collaboration. There is considerable scope and potential for the two sides to have an expanded and more strategic form of collaboration. Yet, for this to occur, new ways of thinking and approaches are needed, including better evidence about the business case for the two to engage with each other. The study seeks to shed light on a topic of increasing interest and significance in a global context where uncertainty, rapid change and complexity are likely to be the hallmarks of humanitarian crises in the foreseeable future.