This chapter focuses on harm reduction policies. It begins with a definition of harm reduction, and then moves into a systematic and chronological survey overview of some of the most significant drug policies and programs operating around the world. They include: the British System of heroin prescription; opioid agonist therapies; needle exchange and syringe programs; supervised consumption facilities; and heroin maintenance therapy. This chapter will provide students with an introduction to a wide range of harm reduction programs, as well as provide a geopolitical overview of where certain harm reduction programs either are or are not currently operating. This chapter will draw on theories to help us better understand why harm reduction programs and policies develop. An important focus here will be on the various obstacles and impediments to harm reduction policy development. Lastly, this chapter will briefly consider some of the challenges to the continued effectiveness of harm reduction policies and programs such as fentanyl and other synthetic drugs.