The South Caucasus is an important region for the study of separatism. While separatist tendencies are present in a large number of South Caucasian ethnic groups, there are significant differences in the degree to which such tendencies have been realized. Why certain groups in the South Caucasus have been more successful than others in pursuing their separatist demands has yet to be adequately explained. The present study employs ethnic bargaining theory to examine the causes of this phenomenon and assesses separatism on the basis of the relationship between ethnic groups, the center, and patron states as well as the effect of ethnic bargaining tools on these relations. The authors hypothesize that ethnic bargaining tools, namely territorial concentration and external support, radicalize ethnic group demands and are directly related to the success of separatist movements. This descriptive-analytical investigation of ethnic separatism in the post-Soviet South Caucasus confirms this hypothesis.