Purpose: This study investigated the impact of changing availability of tamper-deterrent and non-tamper-deterrent oxycodone on prescribing patterns of controlled-release oxycodone across Canada. Methods: We conducted a population-based, serial cross-sectional study of controlled-release oxycodone dispensing from community pharmacies across Canada between October 2007 and April 2016. We calculated rates of dispensing (tablets per 100 population) and reported the relative market share of generic non-tamper-deterrent controlled-release oxycodone. All analyses were reported nationally and stratified by province. Results: After the introduction of a tamper-deterrent formulation, the national rate of controlled-release oxycodone dispensing fell by 44.6% (from 26.4 to 14.6 tablets per 100 population from February 2012 to April 2016). Between December 2012 and July 2013, there was moderate uptake of generic non-tamper-deterrent controlled-release oxycodone (968 452 tablets; 16.0% in July 2013), which appeared to have little impact on the overall rate of controlled-release oxycodone dispensing in Canada. However, the uptake of generic non-tamper-deterrent oxycodone varied considerably by province. By April 2016, 55.0% of all controlled-release oxycodone tablets dispensed in Quebec were for the generic formulation. Elsewhere in Canada, this prevalence was less than 30%, ranging between 1.6% (Prince Edward Island) and 26.9% (British Columbia) at the end of our study period. Conclusions: The changing availability of tamper-deterrent and non-tamper-deterrent formulations of controlled-release oxycodone in Canada has had variable influence on the rate of use of these products across Canada. Future research should explore whether the availability of generic controlled-release oxycodone has led to measurable changes in the safety of oxycodone use in Canada.