The purpose of this study was to determine the suitability of supplementing turmeric and/or mahaleb powders in crackers to enhance phenolic content and antioxidant activity. They replaced wheat flour for 0, 5.0, or 7.5%. The highest bioaccessible phenolics (7,591.90 mg of gallic acid equivalents/100 g dry weight) and phenolic bioaccessibility values (77.94%) were obtained in the 7.5M7.5T sample. Turmeric and/or mahaleb powders' addition had a positive effect on phenolic contents and bioaccessibilities of the cracker samples. In all assays, antioxidant capacities of the crackers supplemented with turmeric and/or mahaleb powders were significantly (P <= 0.05) higher than the control crackers. The results showed that the samples with turmeric and/or mahaleb powders exhibited significantly (P <= 0.05) higher bioaccessible antioxidants than the control sample. Bioaccessibilities of crackers based on antioxidant capacity increased linearly with supplementation increments. Antioxidant bioaccessibility of the crackers ranged between 9.00 to 47.29% for the TEAC(ABTS), 11.54 to 14.47% for the TEAC(CUPRAC) and 12.47 to 20.59% for the TEAC(DPPH). The highest antioxidant bioaccessibilities (47.29%, 14.47%, and 20.59%) in all assays (respectively ABTS, CUPRAC, and DPPH) were obtained in the 7.5M7.5T sample. According to sensorial evaluations, generally, all supplemented crackers scored higher than the control. The taste of the crackers improved by supplementation of turmeric and/or mahaleb powders, as these crackers had typical pleasant mahaleb and turmeric flavour. Overall results suggest that turmeric and mahaleb powders are functional food additives with high phenolic content, bioaccessibility and antioxidant capacity. They can be used in foods, especially in bakery products, without any adverse effect on sensory properties.