||This thesis examines the concept of dependency theory between developing and developed countries. Formerly popular concept explains reasons of underdevelopment in poor countries. This work discusses about two main approaches as the structuralism and neo-marxism. In structuralism part, this work analyzes the main position in economic policy as import substitution industrialization. Later, this work examines the view of neo-marxism as the radical school within economic theory. At the end, we summarize the main benefits of dependency theory from current view.