An introduction to the special issue on sibling relationship processes across the lifespan

Although siblings are significant relationship partners and are influential on individuals’ well-being, only 2.4% of family-focused research examines siblings. The goal of this special issue is to expand the literature on sibling relationships, highlight the importance of sibling relationships across the lifespan, and promote interest in studying this unique and ubiquitous relationship. In the introduction to the special issue, we describe the selection process, and discuss the developmental periods, theoretical frameworks, populations of interest, research design, and main constructs featured in the articles included in this issue. We also give suggestions for future research on sibling relationships. The articles included in this issue move the field forward by improving upon many of the critiques of sibling relationship research.