Simple Summary With the increasing world population and rising meat consumption, sustainable high-quality feed is urgently needed. It was proposed that insects could be a promising alternative feed source, since they have high protein contents and can be reared sustainably on food production residues. Caterpillars of the African cotton leafworm Spodoptera littoralis can be cultivated on different residues of crops and vegetables and larvae of the peach fruit fly Bactrocera zonata can be reared on fruit and vegetable residues. In addition, mass rearing expertise of these two insect species already exists thanks to the sterile insect technique, a method of biological pest control. The nutrient composition of meals from these two insect species was determined and the impact of their meals as feed ingredients for Japanese quail chicks in comparison to soybean meal was investigated. In the feeding trials, 50% of the soybean protein was replaced with B. zonata meal and S. littoralis meal, respectively. For chicks fed with insect meal containing diets, improved growth, feed performance parameters, carcass characteristics and biochemical indices were observed in comparison to a soybean meal-based diet. Consequently, both insect meals represent a promising alternative to soy in the feed of Japanese quail chicks. Abstract A transformation of current livestock production towards a more sustainable operation is crucial to face nutritional and environmental challenges. There is an urgent demand for more sustainable high-quality feed sources to reduce environmental costs. Insects pose a potential alternative since they can be reared sustainably on food and feed residues. Know-how in mass rearing already exists for insect species used in biological pest control, such as the African cotton leafworm Spodoptera littoralis and the peach fruit fly Bactrocera zonata . The impact of a replacement of 50% of soybean meal by S. littoralis and B. zonata meal, respectively, on seven-days-old Japanese quail chicks was investigated in feeding trials. Concomitantly, the chemical compositions of the two insect meals and soybean meal were determined and compared. It was observed that the insect meals had higher protein and fat contents, lower carbohydrate contents and contained more saturated fatty acids than soybean meal. They also had higher methionine, and S. littoralis had a higher lysine content. Feeding trials resulted in improved growth, feed performance parameters, carcass characteristics, and biochemical indices for both insect meals. Consequently, both insect meals represent a promising alternative to soy in the feed of Japanese quail chicks.