AbstractIntroductionAssessing unmet demand for alcohol and other drug (AOD) treatment requires accurately counting those in treatment and determining those in need of treatment. Using updated epidemiological and treatment data, this study sought to provide an updated estimate of the unmet demand for AOD treatment in Australia.MethodsAustralian prevalence rates for alcohol, cannabis, methamphetamine and opioid use disorders were obtained from the Global Burden of Disease and research studies. The estimated proportion of people who would likely not seek or need treatment were subtracted from the diagnosed population. The number of people receiving treatment was estimated using AOD treatment databases and previous research.ResultsAn estimated 752,812 to 1,291,119 people met criteria for a substance use disorder in Australia in 2023. Removing the proportion of people who would not need or seek treatment resulted in between 406,697 and 668,497 people as the potential treatment population. The number of people who received treatment in Australia was estimated at 198,731 people. The unmet demand for AOD treatment was estimated to be between 207,966 and 469,767 in 2023.Discussion and ConclusionsIn Australia, we only treat between 30% and 48% of the population who would seek and benefit from AOD treatment. This is a conservative analysis that assumes only 40% of the alcohol and cannabis use disorder population would seek treatment. The findings from this analysis highlight the continued significant unmet treatment needs of people with substance use disorders. Treatment resources need to be doubled in order to address this unmet treatment population.