‘Unaccompanied minors’ (UAMs) are a group of migrants whose global numbers are increasing. However, little is known about UAMs as data is not systematically collected in any region, if collected at all. UAMs are a diverse group, potentially at additional risk of harm to their health and integrity because they lack protection usually conferred by a family, which can lead to both short- and longer-term health impacts. This review summarises the most recent evidence regarding all the aspects relevant to UAM international migration and health. UAMs are entitled to protection that should follow their ‘best interests’ as a primary consideration but instead detention, sometimes under the guise of protection, remains a widespread practice. There is evidence of good long-term outcomes if these minors are provided with appropriate forms of protection, including health and psychosocial care. Instead, hostile immigration practices persist, which are clearly not in their best interests.