"User-Generated Content (UGC) plays a vital role in driving brand-consumer interactions on visual platforms like Instagram. However, limited empirical research has examined how the quality of UGC—defined by content, design, and technical dimensions—impacts brand engagement in the Quick Service Restaurant (QSR) industry, particularly in emerging markets such as Sri Lanka. Moreover, the mediating role of perceived value (emotional and functional) remains underexplored. This quantitative study employed a deductive approach grounded in positivist philosophy, using judgmental purposive sampling to collect responses from 390 Instagram users in Colombo. Data were analyzed using SPSS v29, applying correlation, regression, and Sobel mediation tests. Findings reveal that high-quality UGC significantly improves both perceived value and brand engagement. Perceived value was found to significantly mediate this relationship, reinforcing the Stimulus-Organism-Response (S-O-R) framework and Uses and Gratifications Theory. Emotional resonance and informational clarity were key in strengthening user-brand interaction. While limited to Instagram and cross-sectional data, the study offers key implications for QSR marketers to encourage visually appealing, emotionally engaging, and functionally useful UGC. Future research could explore longitudinal effects, alternative platforms, or other mediators like brand trust and community belonging."