Professionalism is a key concept in the sociologies of work, occupations, professions and organizations. But professionalism is changing and being changed. The article considers the different ways in which professionalism has been and is currently being interpreted. Beginning with a section on defining the field and clarifying concepts, the second section examines the concept of professionalism, its history and current developments. The third section considers the consequences of changes in work contexts and employment conditions for aspects of professionalism both as an occupational value and as an ideology in the global world.