Most lung function tests are non-invasive and they are widely performed in children and adults for clinical reasons. The prevalence of respiratory disorders is such that there is a considerable amount of research in the area. For both clinical and research applications, professionals involved in lung function testing in children need to be aware of ethical issues pertaining to such testing. In general, these are not specific to lung function testing but are common to other non-invasive procedures. These include the need to recognize the autonomy of the child (appropriate for age and maturity) and the importance of providing information in ways that a child can understand. The issues surrounding consent, confidentiality, and risk-benefit assessment are particularly important in vulnerable groups such as children. Parents, too, have a clear influence on healthcare issues surrounding children and hitherto have not always been appropriately involved. Healthcare professionals have a duty to children and their families to safeguard their psychological, social and emotional well-being, as well as their physical health.