OBJECTIVE: To quantify the current national burden of opioids for osteoarthritis (OA) pain in Australia in terms of number of dispensed opioid prescriptions and associated costs, and to forecast the likely burden to the year 2030/31. DESIGN: Epidemiological modelling. METHODS: Published data were obtained on rates of opioid prescribing for people with OA and national OA prevalence projections. Trends in opioid dispensing from 2006 to 2016, and average costs for common opioid subtypes were obtained from the Pharmaceutical Benefits Scheme and Medicare Australia Statistics. Using these inputs, a model was developed to estimate the likely number of dispensed opioid prescriptions and costs to the public healthcare system by 2030/31. RESULTS: In 2015/16, an estimated 1.1 million opioid prescriptions were dispensed in Australia for 403,954 people with OA (of a total 2.2 million Australians with OA). Based on recent dispensing trends and OA prevalence projections, the number of dispensed opioid prescriptions is expected to nearly triple to 3,032,332 by 2030/31, for an estimated 562,610 people with OA. The estimated cost to the Australian healthcare system was $AUD25.2 million in 2015/16, rising to $AUD72.4 million by 2030/31. CONCLUSION: OA-related opioid dispensing and associated costs are set to increase substantially in Australia from 2015/16 to 2030/31. Use of opioids for OA pain is concerning given joint disease chronicity and the risk of adverse events, particularly among older people. These projections represent a conservative estimate of the full financial burden given additional costs associated with opioid-related harms and out-of-pocket costs borne by patients.