This chapter examines patterns of migrant smuggling and trafficking. Smuggling and trafficking are related, but distinct, phenomena that often arise when states restrict immigration and enforce these restrictions. How many people are trafficked and smuggled around the world? How has our understanding of smuggling and trafficking operations evolved over time? How and why have state policies to address smuggling and trafficking changed? How can states best combat the criminality involved while also protecting migrant rights? Historically, states addressed trafficking, and especially smuggling, unilaterally, if they addressed it at all. However, as states around the world securitized their borders and enforced immigration restrictions in the late twentieth century, there was increasing demand for multilateral action on both smuggling and trafficking. The resulting Protocols to the UN Treaty against Transnational Organized Crime paved the way for an increasingly robust framework for anti-trafficking efforts. The same is not true for smuggling, where there is still considerable disagreement about how best to understand and address it.