Purpose: As accurate and reproducible measurements of spinal curvature are crucial in the examination of patients with adolescent idiopathic scoliosis (AIS), this systematic review aims to report on the reliability and validity of a range of inexpensive and easily administered anthropometric methods of postural asymmetry measurement in an AIS population, to inform practice in a clinical setting. Methods: A systematic search of health research databases located studies assessing reliability and validity of inexpensive and easily administered anthropometric measures. Results: Fourteen studies satisfied eligibility criteria. The methodological quality of included studies ranged from low to high. Validity studies were of moderate to high quality. In total, nine clinically applicable, inexpensive and easily administered anthropometric methods were identified, for assessing AIS curvature. All methods demonstrated high to very high inter-observer and intra-observer reliability. Reported criterion validity of the scoliometer and 2D photographs, when compared to Cobb angle assessed from radiographs, ranged from low to very high. iPhone measurements correlated well with scoliometer measurements. 2D photography results had a moderate to high correlation with 3D topography results. Conclusions: Overall, strong levels of evidence exist for iPhone and scoliometer measurements, with a high to very high reliability and moderate to very high validity. Moderate levels of evidence exist for scoliometer with mathematical formula and clinical examination with moderate and low validity, respectively. Limited evidence exists for aesthetic tools TRACE and AI and 2D photography. These results indicate there are accurate and reproducible anthropometric measures that are inexpensive and applicable in therapy settings to assess postural asymmetry; however, these only exist for measurement in the transverse plane, despite 3D characteristics of AIS. Further research is required into an inexpensive and easily administered method that can assess postural asymmetry in all anatomical planes.