This thesis focuses on existing middle power theories, which are available in the International Relations literature and their applicability to the so-called emerging powers. Despite the increasing attention being devoted to 'emerging' powers such as Brazil, China, India or South Africa, no suitable theoretical framework for the study of this category of states has been established to date. Rather, it has been customary to apply existing middle power theories, which were advanced in the 1980s and early 1990s to account for the forms of power exercised by countries like Canada and Australia, to the study of emerging powers. Yet, it is the overarching this thesis that, despite some attempts at revising middle power theory to suit the distinction between the 'traditional' middle powers and the 'new' or 'emerging' powers, they have not provided satisfactory explanations for the forms of power that emerging powers exercise in the international political economy. To overcome this problem, a set of hypotheses are developed for the study of emerging powers that are embedded in an analytical framework that originates from the New Political Economy approach. Since the New Political Economy approach offers an understanding of structure and agency as mutually constitutive, and of power to exist in both material and ideational form, it is seen to provide a 'broader' insight into the different forms of power exercised by emerging powers than that granted by existing middle power theories.