The article focuses on ethnic differences and the state-minority relationship in Southeast Asia. The diversity and complexity of the human geography of Southeast Asia is rarely surpassed in other parts of the world. Besides recent immigrant Chinese, Indian, European and other communities, the indigenous population have more than twenty-five languages and over 250 dialects. There arethree major religions; and there are profound racial, cultural and demographic contrasts between the coastal areas and the mountainous interiors, between the western two-thirds of Southeast Asia and the eastern third, and between island Southeast Asia and mainland Southeast Asia. New states of Southeast Asia face problems of national cohesion. In all cases, there are centrifugalforces which strain the unity of the state. Some are a result of ethnic differences and some are related to the unjust treatment of minority groups. [Download]