Global counterfeit drugs sold online pose a major public health risk. Unregulated internet pharmacies sell counterfeit medicines to unsuspecting consumers around the world, threatening patient safety. Current enforcement efforts are inadequate, as illicit online drug sales can still be easily found. A coordinated, multi-sector approach is needed involving public-private partnerships between law enforcement, regulatory agencies, internet and payment companies, and others. Through active surveillance of online drug sales, information sharing, and prevention efforts, partnerships can help curb this growing global health threat.