In an era of virtually inexhaustible choices of media channels and messages, the question of what motivates individuals to attend to a particular outlet or type of content becomes particularly pressing. With ample messages available, most mediated communication is a matter of choice. This chapter clarifies what drives such selective exposure. First, a review of technological changes that shape media choice environments is offered, followed by a discussion of different layers of media choice and the terminology connected to selective exposure. Three related research traditions are then reviewed; the chapter concludes with some suggestions for future research.