We often use the term “attachment” to describe our emotional connectedness to objects in the world. We become attached to our careers, to our homes, to certain ideas, and perhaps most importantly, to other people. Interestingly, despite its import and ubiquity in our everyday lives, the topic of attachment per se has been largely ignored in the philosophy literature. I address this lacuna by identifying attachment as a rich “mode of mattering” that can help to inform certain aspects of agency (...) and emotion. First, drawing on insights from Ancient stoicism and developmental and clinical psychology, I suggest that the relevant form of attachment involves a felt need for its object and a particular relationship between the object and the attached agent’s sense of security. I then argue that these features serve to distinguish the attitude from the more philosophically familiar notion of caring. Finally, I show that recognizing this form of attachment as a distinct mode of mattering has important implications for understanding grief. (shrink)