Opioid agonist treatment (OAT) is the provision of medications (methadone and buprenorphine) that activate the opioid receptors to prevent withdrawal and reduce cravings for opioids. Despite its demonstrated effectiveness, barriers to OAT access exist in various areas of law and policy, restricting access for many. This paper identifies barriers to OAT access and potential solutions to improve OAT uptake, in eight sectors--health care system, criminal legal system, family law, housing, zoning, transportation, education & youth, and employment.