Most volumes in the environmental economics literature consider the environment to be a public good and hence write out a role for the private sector in a source of supply. Yet there is ample evidence of the private sector being involved, driven both by profit and altruism. In this talk, Jeff will refer to his recently edited book Protecting the Environment: Privately which provides the necessary conceptual base for the inclusion of the private sector in the environmental protection supply equation and delivers an extensive set of examples in a wide range of contexts. These contexts include both pure-private sector initiatives in terrestrial, aquatic and marine ecosystems and public-private sector ‘joint initiatives’ such as payment for environmental services (PES) schemes. In an economic climate where governments are attempting to reduce expenditures, an increased role for the private sector in the field of environmental protection may be an attractive option for policymakers.