In recent years, discussions on the legal regulation of drugs – and in particular of cannabis – have moved in from the margins of drug policy debates. As of today, over 50 countries have adopted regulatory frameworks for medical cannabis, while a growing number of jurisdictions have regulated adult non-medical use, with many more poised to follow. As these legal frameworks are put in place, it is essential that they are designed to advance social justice, inclusion and human rights. The legal regulation of a scheduled drug is not a silver bullet that solves all the harmful outcomes of prohibition. Legal regulation has the potential to become a powerful tool to redress decades of criminalisation, economic exclusion, and lack of access to appropriate health care. However, legal markets can also be captured by corporate interests, fail to include comprehensive measures to redress the harms brought by the ‘war on drugs’, and further criminalise people that remain in the illegal spaces inevitably persisting outside any regulated market. The 198 members of the IDPC network operate in a wide variety of legal, political, and cultural contexts around the world. As befits this diversity, some IDPC members do actively advocate for legal regulation, while others focus on different public health and social justice measures, such as harm reduction and decriminalisation. But the legal regulation of cannabis, either for medical or adult non-medical use, is fast becoming an unescapable debate. To address this challenge, this Advocacy Note proposes twenty principles that should inform any regulatory framework for cannabis markets, whether for medical or for adult non-medical use.