This paper, through a five-part discussion, explores the rather fragmented international law and policy framework that has emerged to address the threats of ocean acidification. Part 1 highlights how many provisions of the UN Law of the Sea Convention may apply to ocean acidification, including general obligations to protect the marine environment and to control marine pollution. Part 2 examines the limited addressing of ocean acidification to date under the international climate change regime. Part 3 reviews the importance of three marine pollution control instruments in countering ocean acidification. The role of the Convention on Biological Diversity (CBD) in addressing ocean acidification is summarized in Part 4 with one of the most important contributions being two scientific synthesis reports on ocean acidification impacts on marine biodiversity. Part 5 reviews the contributions of UN General Assembly resolutions and processes to furthering scientific cooperation, international adaptation, and mitigation actions. The paper concludes by suggesting possible future law and policy directions for curbing ocean acidification, for example, adopting a global pH target for the oceans and setting a CO2 atmospheric level benchmark that will address both climate change and ocean acidification concerns.