The effects of varying amounts of grape pomace (GP) on Muscovy ducklings performance, digestibility of nutrients, immunological response, caecal microbiota, and carcass traits were studied from 7 to 70 days of age. Four experimental groups (0, 2.5, 5.0, and 7.5 % GP) comprising 200 unsexed 7-day-old ducklings were randomly assigned. The study found that diets supplemented with GP significantly improved economic efficiency, feed conversion ratio, body weight, and weight gain, with the 2.5% and 5.0% GP groups showing the most significant improvement. Duckling diets supplemented with varying levels of GP significantly enhanced digestibility coefficients (organic matter, crude protein, ether extract, and nitrogen-free extract) and intestinal lactobacillus counts than the control group. Also, the study found that ducklings fed 2.5 and 5.0% GP showed significantly improved blood parameters compared to the control group. Duckling fed varying levels of GP showed increased phagocyte index, immunoglobulins (A, G, and M), and blood antioxidant parameters (total antioxidant capacity, glutathione peroxidase, and superoxide dismutase) compared to the control group. The opposite trend was observed for feed consumption and Prominently, intestinal total bacterial count, Escherichia coli, and Proteus spp counts were significantly decreased. It could be concluded that dietary supplementation with 2.5 or 5.0% GP in duckling diets improved duckling productive performance, nutrient digestibility, hemato-biochemical pramateres, and immunological response, with 2.5 or 5.0% GP being the optimal inclusion level.