The Spence Children's Anxiety Scale (SCAS) is one of the most used instruments to assess anxiety symptoms in children and adolescents. Extensive research has been conducted to examine its psychometric properties and to develop other versions of the scale. The objective of this study was to examine the psychometric properties and factorial structure of the SCAS across different versions and populations. This systematic review followed PRISMA guidelines and was registered. APA PsycINFO, Web of Science (Core Collection) and MEDLINE (PubMed) were searched. Fifty-two studies were included in this systematic review. They examined the factor structure, convergent and divergent validity, and internal consistency of the scale. The most supported model was the original six-factor model, followed by the higher order six-factor model for the long version of the SCAS. Studies provided evidence of convergent validity and internal consistency. It is concluded that the SCAS is a valid and reliable instrument for assessing anxiety symptoms in children and adolescents, with a six-factor model structure well supported in most populations. Further research on the psychometric properties and factor structure of other versions of the scale and its application to clinical populations is warranted.