There have been, and continue to be, many calls to reform the drug laws in Australia. Some of the reform proposals concern the legalisation of currently illicit drugs, and the establishment of a regulated market. Other calls are for the removal of criminal penalties for personal use and possession of drugs: “decriminalisation”. The aim of this document is to provide a relatively simple summary of the various models for the decriminalisation of personal use/possession of illicit drugs. We take current Australian laws as our starting point, and describe four possible models with reference to Australia. Nonetheless this work is also relevant for other countries. Our hope is that this paper provides a basis for generating a shared understanding of the key features of different decriminalisation models; enables robust debate; and operates as a decision-support tool for those considering decriminalisation.