Harms associated with alcohol and other drugs (AOD) cost Australia over $25 billion per year. The law plays a central role in managing these harms. Legal responses to AOD and the key concept of 'addiction' are often inconsistent. These variations have unintended and often adverse, economic, social and health implications. Using an international comparative method involving Australia and Canada, this research seeks to critically analyse legal approaches to addiction, isolating the strengths and weaknesses of different approaches. This project aims to inform more productive legal responses to addiction, and is expected to produce recommendations for improving AOD-related outcomes in Australia.