Those actors that attempt to influence business approaches to social responsibility are typically concerned with preventing businesses from causing harm or holding businesses accountable for harmful activities when they occur. In post-conflict settings, these twin aims are particularly important given the innumerable instances of businesses undermining transitions from conflict to peace through harmful practices. However, businesses can also be positive agents of change. As an emerging discourse on business and peacebuilding is suggesting, businesses can contribute positively to transitions from conflict to peace in a range of ways. But can other actors influence businesses to engage in peacebuilding processes? Can they require, induce and persuade positive business-based contributions to peacebuilding? If so, how? Examining two case studies on Northern Ireland and South Africa, I will argue that different actors can influence businesses to act as peacebuilding agents. I use the findings from these case studies to consider opportunities for thinking about a global policy instrument on business and peacebuilding.