Horizontal root fractures are frequently occurring consequences of acute traumatic dental injury (TDI). They are described as fractures separating the root into coronal and apical segments, with the fracture lines being completely or partially confined within the bone. Depending on the degree of injury, different treatment regimens may be applied. However, because the overall prevalence of root fracture is low, health-care professionals are often insecure regarding appropriate management. In general, root fracture treatment aims to preserve the functional integrity and aesthetics of the teeth involved. Treatment failure may eventually lead to tooth loss, with potentially negative lifetime consequences, such as impaired orofacial development. Altogether, it is indispensable for the health-care professional to know the biological foundation, diagnostic approaches and appropriate treatment modalities for root-fractured teeth. This chapter provides information on all these aspects, as well as the currently recommended recall regime and expected outcomes.