<p>Safer supply is a medical form of harm reduction in which a patient is prescribed a drug to which they are addicted. Despite ample high-quality evidence that it is a safe and effective last-line treatment for severe, treatment-refractory substance use disorders, safer supply is not widely used or advocated. This is likely due in part to ethical concerns, but I contend that safer supply is ethical by both general moral standards and the professional ethical standards of healthcare. Recent defenses of various harm reduction interventions argue that they are permissible regardless of the moral quality of the drug use they facilitate. I critique those defenses and argue that safer supply is permissible by general moral standards because the medical drug use it supports is not immoral. Furthermore, safer supply does not run afoul of biomedical ethics because it is not maleficent, unhealthful, or nonconsensual. As an evidence-supported and ethically permissible practice, safer supply merits wider use and advocacy.</p>