Chicken eggshell, a poultry waste material, is a potential but poorly recognised source of calcium that can be used by humans to increase their dietary calcium intake by incorporating it into foods. This study was aimed at assessing the effects of eggshell powder supplementation at 5, 10, 15, and 20% levels on the chemical composition, sensory characteristics, and calorific value of the biscuits. Calcium absorption from supplemented biscuits was also determined. The inclusion of eggshell powder resulted in significant variations in the chemical composition of biscuits. It profoundly increased the mineral content, mainly calcium from 43.57 mg 100 g<sup>–1</sup> to 1 054.7, 2 186.7, 2 941.6, and 3 843 mg 100 g<sup>–1</sup> at 5, 10, 15 and 20% supplementation level, respectively. Substantial changes in the sensory quality of biscuits were also observed with corresponding rises in eggshell addition levels. Biscuits prepared with 5 and 10% supplementation levels were found acceptable in terms of sensory attributes. The in vivo study affirmed the absorption of calcium from eggshell powder and it was found highest (41.83%) at 5% supplementation level. Conclusively, supplementation of biscuits with eggshell powder might be an attractive source of dietary calcium intake without any significant adverse effects on biscuits quality up to 10% supplementation level.