The Optional Protocol to the Convention against Torture ('OPCAT') is a unique, action‑based treaty which is designed to protect people everywhere who have been deprived of their liberty. Detention puts individuals in a very vulnerable position, as they are at the mercy of the State and rely on the authorities for even their most basic needs. This raises a very real risk of human rights abuses - a risk which can only be mitigated by strong oversight mechanisms. The OPCAT provides a framework for such mechanisms, and is currently being considered for ratification by Australia. This article sets out some of the issues associated with ratification, including the potential costs, the places of detention it is likely to cover and which bodies are likely to be involved in implementation. It also explains that the OPCAT is highly relevant to Australia because it is about much more than just torture.