In this chapter, we first introduce the questions of when and how children start using connectives and discourse relations during their first years of life. We will see more specifically that mastering the complex form-function mappings involved in the understanding of many connectives is a complex task for young children. In addition, we will present research investigating school-age children’s comprehension of connectives, and show that it is only around the end of their primary school years that they fully understand frequent connectives. We will explore the causes of these difficulties, and discuss the differences between various connectives and discourse relations. We will then move on to other studies analyzing the way older children understand connectives, and see that their acquisition is not fully in place after primary school years, as teenagers keep developing their competence with connectives. Finally, we will briefly discuss the acquisition of connectives and discourse relations by children suffering from linguistic or cognitive impairments such as SLI and autism.