This study was conducted to assess the efficacy of three agar-free artificial diets (D1, D2, and D3) for the mass rearing of fall armyworm, (FAW)  Spodoptera frugiperda under controlled laboratory conditions (27 ± 1°C; 70 ± 5% relative humidity; 14:10 light : dark photoperiod), in comparison to natural food sources (castor leaves and lettuce leaves). The findings demonstrated that all three artificial diets supported efficient rearing of FAW. Diet D1 yielded the most favorable outcomes, resulting in the shortest total immature development period (24.25 days) and the lowest larval mortality percentage(5.00%), followed by D2 (7.00%). In contrast, larval mortality was highest on lettuce leaves (15%), followed by castor leaves (12%) and D3 (9%). Pupal mortality was highest on lettuce leaves (11.76%) and lowest on D1 (6.32%). The mean fecundity was highest for D1 (785 eggs/female), followed by D2 (730 eggs/female), D3 (665 eggs/female) and castor leaves (628 eggs/female), with the lowest fecundity observed on lettuce leaves (576 eggs/female). No statistically significant differences were detected in fertility across the diets and natural food sources. These results demonstrate how diet D1 outperforms other diets and natural food sources in fostering development and fitness indicators for S. frugiperda.  These outcomes were necessary for the ongoing rearing of this insect in sufficient numbers to support studies on creating integrated pest management systems.