Based on the social role theories of Linton and de Singly, the article presents the sibling’s social role over the life course, as rendered by contemporary French-language sociology, both explicitly and implicitly. Most publications focus on childhood and adolescence, especially in blended or poor large families. A sibling is an actor of socialization, can be a companion, a complice, a confidant, a rival, or may remain distant. Birth order, sex or (non)living in the same household are of importance. The adult siblinghood is little studied; based on the literature it is difficult to trace its stages in matter of the role. Yet the role of a "kinkeeper", a confidant, a helper in need can be traced. Siblings are involved in building family memory. Sibling interaction is also expected in relation to the status of children, heirs and successors of the same parents. The analysis of literature revealed missing places requiring further research and showed the great potential of French-language sociology.