This chapter examines the practice of internal self-determination in the context of the ethnic conflict in Sri Lanka. It examines the Tamil minority struggle for self-determination, and how the demands for both federalism and separatism have been made through the broader language of self-determination. The chapter shows how different minority groups make demands which amount to internal self-determination, how the government responds to such demands, and also how the language of internal self-determination has been viewed skeptically by the Tamil minority. The chapter shows the potential and problems internal self-determination as a concept holds in the context of a protracted ethnic conflict.