Issue On 17 October 2018, Canada legalised non‐medical cannabis. Critically, the cannabis market in Canada has changed considerably since legalisation. In this scoping review, we identified available evidence on changes in cannabis‐related health harms following legalisation and contextualised findings based on legal market indicators. Approach Electronic searches were conducted to identify studies that compared changes in cannabis‐related health harms pre‐ and post‐legalisation. We contextualised each study by the mean per capita legal cannabis stores and sales during the study period and compared study means to per capita stores and sales on October 2021—3 years following legalisation. Implications and Conclusions Some measures of cannabis harms have increased since legalisation but studies to date have captured periods of relatively low market maturity. Longer‐term monitoring of health harms as the market continues to expand is indicated.