<p>Increasingly, Artificial Intelligence (AI) assistants are used to optimize communication goals by modifying, augmenting, and generating messages in human online interactions. Scholars are just beginning to recognize the potential of AI-Mediated Communication (AI-MC) to transform how people communicate and manage impressions, and this article helps advance research in this area by conceptualizing ways in which using AI-MC can lead to perceptions of self-extension. We first unpack the conceptual history of technological self-extension and trace the development of a three-pronged framework that has been applied to research on smartphones, including functional, ontological, and anthropomorphic dimensions. We then synthesize the literature on smartphone self-extension with defining features and uses of AI-MC to advance propositions about ways in which its use can foster user perceptions of functional, ontological, and anthropomorphic self-extension. As we explain, AI-MC refers to AI’s capacity to modify, augment, and generate communication, and each of these distinctive processes suggests distinctive mechanisms and implications for self-extension. The article concludes by addressing how AI-MC and smartphones are converging and advances considerations for self-extension and how scholars study it.</p>