Non-invasive ventilation (NIV) is a well recognised and increasingly prevalent intervention in the paediatric critical care setting. In the acute setting NIV is used to provide respiratory support in a flexible manner that avoids a requirement for endotracheal intubation or tracheostomy, with the aim of avoiding the complications of invasive ventilation. This article will explore the physiological benefits, complications and epidemiology of the different modes of NIV including continuous positive airway pressure (CPAP), non-invasive positive pressure ventilation (NIPPV) and high-flow nasal cannula oxygen (HFNC). The currently available equipment and patient interfaces will be described, and the practical aspects of using NIV clinically will be explored. The current evidence for use of NIV in different clinical settings will be discussed, drawing on adult and neonatal as well as paediatric literature.