In recent decades, the prevalence of demyelinating diseases in paediatric patients has increased rapidly. In this context, there is an increasing need for the study of this pathology in children to enable timely diagnosis and early prescription of highly effective pathogenetic treatment. Neuromyelitis optica spectrum disorders (NMOSD) are a group of severe demyelinating disorders that are united by a single pathogenetic mechanism and primarily affection of the optic nerves and spinal cord. The review presents the main clinical and epidemiological features of NMOSD in the paediatric population. The issues of pathogenesis, which is based on the formation of antibodies against aquaporin-4, and possible therapeutic targets are discussed in detail. The diagnostic criteria and the underlying clinical manifestations as well as their characteristics in childhood are analysed. We present a differential diagnostic framework of the most common diseases, which have to be distinguished from NMOSD in children. Particular attention is paid to the pathogenetic treatment of exacerbations and targeted therapy to prevent exacerbations, which has relatively recently proven its efficacy and been approved for use in paediatric patients.