When a country is sanctioned for violating international rules today, it is usually targeted by several different entities. The degree to which sanctions by different senders overlap remains a largely unexplored phenomenon. In this paper, we examine the extent of sanctions cooperation, i.e. joint action among major sanctions senders (the US, the EU, and regional organizations) against identical targets. We then map regional patterns and evaluate one potential explanation for them. Our analysis leads to three major findings. First, sanctions overlap is predominant and has consistently increased over the last three decades. Twothirds of sanctions involve more than a single sender. Targets today are usually subject to punishment by at least three different sanctions senders (up from one in 1980) and sometimes up to six different senders. Second, world regions vary widely in the extent of sanctions cooperation, the profile of sanctions senders, and their interactions. Third, to explain variation in sanctions cooperation, we find that hegemonic stability theory does not provide much leverage. We conclude by outlining avenues for future research on sanctions cooperation relating to sanctions onset and effectiveness.
