This review answers recent calls to consider the transformative role of transnational professionals in contemporary globalization. It departs from the dominant perspective, which views professions as constrained by states’ geographical boundaries and by organizations such as nationally based professional associations. Transnational professionals have particular characteristics: they combine high-level abstract knowledge, high mobility across national and organizational settings, social and cultural capital, and distributed agency to shape global practices. Over the past two decades, a vibrant research stream has emerged on these professionals and their boundary-crossing work, raising new questions about agency, territoriality, and power. We examine transnational professionals across a range of occupations and sectors, as well as world regions, extracting the implications for sociological theory and methods. We outline a scholarly agenda highlighting the opportunity structures and likely trajectories for those who locate themselves in transnational professional spaces, suggesting how they can be investigated in future research.