Abstract
Although siblings may differ considerably, the similarities between them are often an important source of emotional support in one’s life and influence one’s life course trajectories. In this review on the topic of sibling relationship and cross-sibling effect interactions, we aim to encourage research interest and facilitate knowledge building. We begin our review by highlighting how the parental home may induce differentiation between siblings. Next, we illustrate the theories explaining sibling similarities and differences and discuss the factors that stimulate these. Throughout the review, we do not only highlight the complex mechanisms by which siblings imitate yet differentiate themselves, but also mutually relate to their life courses and education. New understandings of how similarities between siblings can simultaneously act as powerful influences and negative examples are provided.