The objective of this systematic review was doing a search of the validity of neck perimeter as a marker of adiposity in children and adolescents as well as in adults. A systematic search for articles published before June 30, 2017 was conducted using the PubMed and Web of Science databases. Original studies, in Spanish or English, were searched to analyze the association between neck circumference and any other marker of adiposity. MeSH (Medical Subject Heading) categories were used in PubMed. The search criteria used were: (("neck circumference" or "neck diameter") AND ("Body Composition" [Mesh] OR "Anthropometry" [Mesh])). This search was repeated in Web of Science. We identified 494 studies, of which 47 were finally selected for this review. From the total, 66% of studies (16 in children and adolescents and 15 in adults) only specify that there is a relationship between neck circumference and body mass index or waist circumference, waist/hip circumference ratio in children and adults. We also observed that neck circumference was directly associated with adiposity markers indirectly measured by reference methods such as computed tomography (CT) or dual-energy x-ray absorptiometry (DXA) in adults. Conversely, no studies were found in children and adolescents. In conclusion, neck circumference is associated with doubly-indirect markers of total and central fat mass in children and adolescents, while in adults it is associated with adiposity parameters measured with indirect and doubly-indirect methods. Further studies including methods that address the association between neck circumference and body composition analyzed using reference methods are required, especially in children and adolescents.