The quality of water entering the coastal waters of the Great Barrier Reef continues to be of urgent concern for policy makers. Beef grazing and sugarcane cultivation pose special threats at the catchment scale, and past policy approaches and millions in investment have largely proved insufficient to reverse the associated decline in water quality. In this paper, we examine the role of regulation - as one tool of governance - in addressing threats to water quality to the Great Barrier Reef. By adopting a focused study of sugarcane and cattle grazing, and by drawing upon recent developments in regulatory theory, we evaluate the approaches adopted by government, including the recent re-introduction of legislative measures targeting nutrient and sediment loads. Scientific and government consensus appears to be that regulation should form part of a functioning environmental governance system, but it must also be supported by other measures such as economic incentives, education and outreach. Where regulation of land use is required, best practice suggests it should be risk-based, responsive, and cognisant of the regulated industry's attitudinal settings.