Over several decades, a combination of historical, economic, and political factors have influenced the multifaceted phenomenon of Vietnamese return migration from Cambodia. This article examines the return migration of Vietnamese from a historical perspective with document and contextual analysis, revealing a broader picture of the socio-economic and political dynamics in Cambodia and the historical relationship between Cambodia and Vietnam. Before the 1990s, return migration was significantly influenced by colonial-era migration policies and pervasive anti-Vietnamese sentiments. These factors led to violent repression and forced evictions under regimes such as Lon Nol and the Khmer Rouge, profoundly impacting the Vietnamese community in Cambodia. In contrast, administrative governance and economic factors have become the key determinants of Vietnamese return migration in the contemporary period. Understanding the underlying causes and mechanisms that create the situation for Vietnamese in Cambodia and their return is crucial, serving as a basis for addressing their current challenges and promoting their social integration in both countries.