On what basis are sibling relations made and negotiated and how do they change over time? How do siblings provide support, but also create pressure or conflict? Despite their importance as models for or contrasts to marriage, friendship, and nation, sibling relations have been largely ignored in anthropology. In this volume, the contributors provide a conceptualization of siblingship as shared parentage, exchange, and experience. They explore what makes these relations worth maintaining and how they contribute to wider community processes, material support, and emotional connection. The ethnographic case studies provide detailed descriptions of lived sibling relations in various settings across the globe.