This introduction to the special section charts the ways in which the concept of vigilance has been loosely conceptualized at the intersection between security, surveillance, and border studies. It rethinks vigilance through the conceptual lens of vigilance regimes, as well as through the productivity of watchfulness in different contexts. Vigilance is conceptualized as an assemblage of moral ideas, belonging, increased attention, and social practice, located in certain sociopolitical contexts, concrete spaces, and technologies. Regimes of vigilance are defined as complex assemblages of practices and discourses that mobilize alertness for specific goals, which are embedded in particular materialities of watchfulness, and which in turn have effects on social practice and processes of subjectivation. This introduction calls for greater analytic attention toward the agency that vigilance produces, and seeks to define vigilance and the regimes that it constitutes, offering a productive lens for the study of socially mobilized alertness.