Because human trafficking is a covert activity and victims sometimes hesitate to disclose it legally and formally, the definition of human trafficking differs from nation to nation, and the precise frequency of human trafficking worldwide is still unknown. The notion of human trafficking and its different forms are examined in this chapter. Through the material currently available, the prevalence of human trafficking in various nations and around the world will be investigated. In particular, the risk factors for becoming victims and traffickers will be examined, along with other psychological elements, such as individual, societal, and cultural aspects of human trafficking. Many different theories have tried to explain human trafficking on different dimensions, and a clear picture of the entire process of human trafficking is yet to come. Theories are explained in the chapter. The problem of under-reporting of human trafficking poses significant issues in assessing the actual prevalence of human trafficking, its networks, and the gravity of the problem. Issues related to the under-reporting of this crime will be explored.