<p>Economic and political decisions are increasingly made in international organizations (IOs). A distinctive feature of many IOs is that they operate under a system of rotating leadership (e.g. a committee chair that rotates annually). Despite the widespread use of such systems and their potential value to interest groups, we know surprisingly little about how interest groups respond to rotating leadership in IOs. Using both micro- and macro-level data on the economic performance of commercial lobbyists in the European Union, I show that interest groups respond strategically to short-term shifts in leadership. Specifically, when a country takes over the rotating EU Council Presidency, interest groups increase their use of commercial lobbyists to gain access to policymakers from the presiding country.</p>