The number, range and foci of voluntary initiatives have been growing rapidly over the last decade, but there is still debate as to whether they work 'on the ground'. The paper begins by defining voluntary initiatives and considers their relative strengths and weaknesses. The main factors contributing to their effectiveness-monitoring, transparency, enforcement, content and compulsoriness-are discussed and are then reviewed in light of an Australian case study of a mining industry initiative. Interviews with mining industry executives and other stakeholders are used to offer insights into the ways in which the efficacy of voluntary initiatives might be improved. It is here that a paradox emerges: the voluntary initiatives with the most potential for success appear to be those that are, effectively, compulsory. The paper concludes by discussing the key ways in which 'compulsory' voluntary initiatives might differ from command-and-control regulation and the broader implications of this apparent movement towards the privatisation of regulation.