Background: In recent years, the use of social networking sites has rapidly increased, enabling people to communicate more efficiently, quickly, and effectively, as well as to access and share information in real time. Accordingly, various research tools and measurement instruments have been developed to assess the impact of social media on individuals’ daily lives. However, most of these instruments primarily focus on the duration and frequency of use, failing to comprehensively capture the true influence of social media. Therefore, there remains a need to evaluate social media use more broadly. Aim: Determine the reliability and validity of the Social Media Use Scale among adolescents. Material and Methods: This analytic cross-sectional study was conducted among 421 students aged 12–17 years (mean age 15.1±3.6), including 43.7% male and 56.3% female participants. The study assessed the reliability and validity of the Mongolian version of the Social Media Use Integration Scale (SMUIS). Construct validity was examined using Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA), while reliability was evaluated using Cronbach’s alpha coefficient. Results: The Mongolian version of the Social Media Use Integration Scale revealed two subfactors (eigenvalue > 1.0). In the principal component analysis, all 10 items showed sufficient factor loadings (≥ 0.4) with no cross-loading items (<0.4). Structural regression analysis indicated positive and significant effects among the subfactors (B=0.42–0.82). The reliability of the validated questionnaire was acceptable, with Cronbach’s alpha values above 0.6. Conclusion The Mongolian version of the Social Media Use Integration Scale demonstrated satisfactory validity and reliability and can be appropriately used to assess adolescents’ electronic media use. Further studies are recommended to test the reliability of this instrument among other population groups.