This study evaluated the impact of thyme powder supplementation on the hen egg production (HD%), total egg production, egg quality, antioxidant and biochemical parameters of laying hens. One hundred and eighty Hyline Brown hens, 40 weeks old were randomly divided into 9 groups of 20 hens and subjected to one of the following treatments: T 1 (control diet), T 2 (5g/kg of thyme), and T 3 (10g/kg of thyme). Each treatment was tested using three groups of hens, which were subject to treatments from 40 to 47 weeks of age. The productive metrics were measured on daily and weekly basis in the period from 40 to 47 weeks of age, while the egg quality was measured after 56 days. Hematological, biochemical and antioxidants parameters were also determined at the end of the experiment. The results showed that the egg production and feed conversion ration were significantly improved in both thyme treatments (T 2 and T 3 ). Also, the PCV (%) and the WBC count. However, there was no significant difference in the egg quality between the thyme-treated and control hens. The hens on thyme-supplemented diets were found to have lower serum cholesterol concentration than those of the control. Supplementing a laying hen's diet with thyme significantly increased glutathione, while, decreased the malondialdehyde, AST and ALT activity in comparison to the control. Therefore, it can be concluded that thyme additives can be used in laying hens diet to improve egg production, egg quality, antioxidant and biochemical parameters in a dose-dependent manner.