Fictionality is a term used in various fields within and beyond literary theory, from speech act theory through the theory of fictional worlds, to theories of “as if.” It is often equated with the genre of the novel. However, as a consequence of the rhetorical theory of fictionality developed from the early 21st century, the concept has gained ground as an autonomous communicative device, independent of its relation to any genre. Theories of fictionality have been developed (1) prior to the establishment of fiction as a genre, with Plato, Aristotle, Philip Sidney, and Pierre Daniel Huet; (2) with the establishment of fiction by Blankenburg and some of the first novelists, such as Daniel Defoe and Horace Walpole; (3) after the establishment of the novel, with Samuel Taylor Coleridge, Hans Vaihinger, John Searle, Kendall Walton, Dorrit Cohn, Richard Walsh, and others. From the 1990s, the debates on fictionality have centered on questions of whether fictionality is best described in terms of semantic, syntactic, or pragmatic approaches. This includes discussions about possible signposts of fictionality, encouraged by the semantic and syntactic approaches, and about how to define the concept of fictionality, as either a question of text internal features as argued by the semantic and syntactic theorists, or as a question of contextual assumptions, as held by the pragmatists. Regarding fictionality as a rhetorical resource, among many other resources in communication at large, has a number of consequences for the study of fictionality and for literary theory in general. First, it contributes the insight that literature is similar to other acts of communication. Second, overtly invented stories do not have to follow the rules of non-invented communication. Third, a rhetorical approach to fictionality makes visible the ways in which fiction interacts with and affects reality, in concrete, yet complicated ways.