Introduction: Scoliosis is characterized by an abnormal lateral curvature that may occur during a child’s growth period. Early detection and intervention are needed to prevent the progression of abnormal curvatures. While the gold standard for diagnosing idiopathic scoliosis is x-ray imaging, there is a quick and easy way to perform screening, i.e., using a smartphone. A mobile application with a built-in inclinometer and simple scoliosis tests may help detect scoliosis. Therefore, this study aimed to assess the ScoScreen mobile application’s content for early screening of AIS. Methods: We recruited five physiotherapists with more than five years of experience in paediatric and musculoskeletal and one spinal surgeon. The validity of this study was assessed using a content validity form. Content validity was assessed by calculating the Item-level Content Validity Index (I-CVI), Scale-level Content Validity Index (S-CVI), and modified kappa. Results: The results show that the content validity of ScoScreen has an excellent level of content validity (I-CVI=0.83 – 1.00). The average approach’s overall content validity index was high (S-CVI/Ave=0.94). All items in this study were excellent, with the kappa scores greater than 0.74 (kappa= 0.816 – 1). Conclusion: The development of ScoScreen for early screening of AIS was proven to have excellent content validity in this study. As a result, the Scoscreen mobile application is appropriate for early detection of AIS in terms of its content.