This chapter begins by exploring the development of theories of professions, a key group in liberal democratic societies – the definition of which has been much debated. The focus then shifts to consider a range of contemporary theories of professions in the Anglo-American context – principally, the taxonomic approach including trait and functionalist perspectives, symbolic interactionism, Marxism, Foucauldianism and discourse analysis. The currently more influential neo-Weberian analysis is then outlined, with an indication of its main benefits compared to the previous theories discussed. The weaknesses of neo-Weberianism in practice are also examined, although it is argued that these are counteracted when it is appropriately employed. Moreover, its characteristic focus on exclusionary social closure provides much broader scope than sometimes appreciated in its application to a wider span of occupations and societies. Nonetheless, the advantages of combining this approach with other theories, particularly the complementary frameworks of Bourdieusianism and neo-institutionalism, are acknowledged. The chapter draws to a conclusion by examining recent challenges to professions and the way in which they have been addressed from a neo-Weberian perspective. These challenges include, amongst others, those posed by clients and citizens, the state and corporatisation. The chapter concludes by assessing, primarily from the viewpoint of neo-Weberian sociological theory, the role that professional groups may play in future in a fast-changing world.