The article gives an empirical overview of the international spread of 22 environmental policy innovations. The policy innovations examined in the article include administrative institutions (e.g. environmental ministries, scientific advisory bodies), laws (e.g. soil protection laws, packaging waste laws), instruments of environmental policy integration (e.g. national environmental policy plans, environmental impact assessment), energy taxes and eco-labels. On this empirical basis, recurring patterns in the global spread of environmental policy innovations are identified and linked to specific causal mechanisms through which this change occurs. In particular, the paper demonstrates how and to what extent non-obligatory diffusion, legal harmonization and coercive imposition matter as mechanisms of global environmental policy convergence. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.