This chapter examines traditional theories in global politics. It begins with a discussion of early liberal approaches, with particular emphasis on liberal international theory whose proponents include U.S. President Woodrow Wilson and Norman Angell. Liberal international theory is characterised by an optimism concerning the prospects of a peaceful international order established through strong international institutions underpinned by international law. The chapter proceeds by considering the emergence of ‘realism’ as a general approach to the study of politics, along with the different approaches to the study of international politics following World War II, including positivism. It also explores the rise of the English School and the concept of international society before concluding with an analysis of neo-liberalism and neorealism that resulted from revisions of both liberalism and realism in the post-war period.