<p>The combination of several varieties of millet can enrich snack nutrition and enhance sensory acceptance. This study investigated the effect of the composite millet flour on the physicochemical, textural, and sensory attributes of millet snacks subjected to deep-fat frying. I-optimal mixture design was used to determine the optimal formulation. It reveals significant effects of the millet level on fat content, bulk density, volume change, <i>L</i>*, color change, texture, and sensory attributes. The increased pearl millet (PM) and proso millet (PRM) levels increased the fat content due to the higher fat content of PM and the oil absorption capacity of PRM. The snacks exhibited the least bulk density (437.64&#xa0;kg/m³) and the highest volume change (1.75) at higher PRM levels. Snacks with 40% PM, 13.33% finger millet (FM), and 21.67% PRM had the highest hardness (10.74 N). The selected formulation includes PM (35%), FM (20%), and PRM (20%), with an improved texture and sensory score of 7.2/9 for overall acceptability. Correlation analysis highlighted strong positive associations between <i>L</i>* and <i>b</i>* (0.86). Multivariate analysis using principal component analysis and hierarchical cluster analysis shows the relationship between responses. The study highlighted the potential of composite millet flour in snack production, providing insights for selecting formulations to improve product quality and consumer acceptance, demonstrating the successful development of gluten-free millet snacks.</p>