In Canada, provincial and territorial laws address circumstances in which a substitute decision-maker may be appointed for an adult deemed legally incapable of making decisions in one or more areas of life. We searched for provincial and territorial laws that explicitly address substitute decision-making about research participation, and found significant differences among Canadian jurisdictions. In some provinces and territories there is no direct statutory guidance on the issue. Differences among jurisdictions that address substitute decision-making about research in legislation include whether judicial intervention is required to authorize the substitute decision-maker, whether any advance directive in place must explicitly authorize the decision about research in order for a proxy to consent, and how risk and benefit thresholds beyond which substitute consent to research is prohibited are articulated. It is imperative that government, researchers, and the Canadian public revisit the principles underpinning substitute decision-making about research in light of national and international norms, in order to lend clarity and consistency to this area of law and research practice.