This chapter focuses on how the technoself develops in children through relationships with a “personal” robot technology, robotic pets, especially the robotic dog AIBO. Drawing on studies of children and AIBO as well as similar robotic technologies, I examine children’s ideas about and behaviors toward such robotic pets in order to describe three domains of the technoself: (1) ideas about the robot (the technological object); (2) ideas about the child’s relationship with the robot; and (3) ideas about the self-in-relationship with the robot. A dynamic developmental perspective is applied to each of the three domains of cognition and behavior, technological object, relationship, and self-in-relationship, that make up the technoself. This perspective asks how variability in child characteristics, such as developmental level, gender, temperament, personality or intelligence; in contextual factors, such as family background or prior experience with other technologies; and in robotic pets themselves predict these three aspects of the technoself.