In Australia, threshold quantities of illicit drugs act as an indicator of supply offences in distinguishing traffickers from users. This is problematic because it can be difficult for the courts to discriminate between heavy users or ‘social suppliers’ and ‘dealers proper’. Currently, there is no systematic analysis of how the judiciary in Australia navigate the relationship between different types of supply and the consistency and proportionality of the sentence applied. This analysis maps out how current sentencing practices respond to offenders involved in ‘social supply’ and ‘minimally commercial supply’ who are charged with drug trafficking. It makes recommendations that could inform future drug law reform, including that review is needed of the system of thresholds, that sentencing objectives of general and specific deterrence be reconsidered in cases of social supply and minimally commercial supply, and that consideration be given to expanding the scope of current diversion programs to accommodate the needs of the types of offenders and offending behaviour addressed in this study.