This article deals with the situation of the ethnic Vietnamese in Cambodia, and the attitudes and policies of the Cambodian authorities towards that minority. Patterns of Vietnamese migration to and from Cambodia are studied with the aim of identifying the dynamics behind them. As anti-Vietnamese sentiments have been regularly displayed by the Cambodian élite and in the policies of the Cambodian authorities, the roots and effects of these attitudes are explored. The anti-Vietnamese discourse in Cambodia shows that the perceptions of Vietnam as a neighbouring state influences the attitudes towards the Vietnamese minority. Discriminatory policies implemented by the Cambodian authorities and attacks instigated by such policies had led to the virtual elimination of the Vietnamese minority in the 1970s, when some 420,000 Vietnamese were expelled or fled to Vietnam. Seen in this perspective, the repeated politically motivated attacks on ethnic Vietnamese in recent years present a real threat to the Vietnamese community at large.