An important feature of the new public management paradigm is the increasing reliance on voluntary codes rather than coercive mandatory regulation to achieve public policy objectives. Often, the proponents of new public management overlook the important contributions of policy entrepreneurs within regulated firms in popularizing such codes. Focusing on the environmental policy arena, this article documents that such policy entrepreneurs—corporate environmental entrepreneurs—exist in many corporations and significantly influence firms’ adoption of progressive environmental policies. This article uses survey data from firms in 16 countries to examine the role of corporate environmental entrepreneurs in the context of an international voluntary code that seeks to encourage firms to adopt environmentally progressive policies.