Drawing on the Global Policing Database (GPD), this review assesses the impact of supplier arrests and seizures on drug crime, drug use, drug price, drug purity, and drug harm outcomes. Just 13 impact evaluation studies (reported in 18 documents) met inclusion criteria. An evidence and gap map was constructed, showing that research to date relates primarily to drug harms, followed by drug crime and drug price, and that there are significant gaps in the impact evaluation literature. The results of this review demonstrate the limited amount of high-quality scientific evidence that can be used to examine the impact of supplier arrest and seizure on a range of drug-related outcomes.