Based on the research papers within this special issue, this overview discusses similarities and differences in stakeholding in drug user opioid substitution treatment policy in Britain, Denmark, Italy, Austria, Poland, and Finland. It explores factors that have influenced stakeholder activity, including the importance of crisis, the impact of evidence, the availability of resources, the wider political context, the influence of moral frameworks and ideologies, and the pressure of external influences. The paper highlights the important differences in the emergence and evolution of stakeholder groups and in the political, cultural, and economic circumstances, which both constrain and enable their activities.