Everyday life is increasingly mediated by technology. Technology is rapidly growing capacity and complexity, especially evident in developments in artificial intelligence and big data analytics. As human-computer interaction (HCI) endeavors to examine and theorize how people act and interact with the ever-evolving technology, an important, emerging concern is how the self—the totality of internal qualities such as consciousness and agency—plays out in relation to the technology-mediated external world. To analyze this question, we draw from Michel Foucault’s ethics of “care of the self,” which examines how the self is constituted through conscious and reflective work on self-transformation. We present three case studies to illustrate how individuals carry out practices of the self to reflect upon and negotiate their relationship with technology. We discuss the importance of examining the self and foreground the notion of care of the self in HCI research and design.