This study was conducted to investigate the effect of adding different levels of (Thymus vulgaris) leaves powder to the diet on some egg quality traits. A total of 300ISA Brown hens, 23 weeks old were randomly assigned for 4 treatments of 75 laying hens each. Each treatment constitutes of 3 replicates with 25 laying hens each. (Thymus vulgaris) leaves powder was supplemented to the diet of hens at the levels of 0 (control group; T1), 500 mg/Kg of diet (T2), 750 mg/Kg of diet (T3) and 1000 mg/Kg of diet (T4). Egg quality traits included in this study were: egg weight, yolk diameter, yolk height, yolk weight, shell weight, shell thickness and haugh unit. Results revealed that feeding the birds diet contains different levels of (Thymus vulgaris) leaves powder (T2, T3, T4) resulted in significant improvement as regards egg weight, yolk diameter, yolk height, yolk weight, shell thickness and haugh unit during the periods of this experiment and concerning the (Thymus vulgaris) leaves powder means of these traits. Thus, (Thymus vulgaris) leaves powder can be used as one of the important nutritive additives that added to laying hens for improving some egg quality traits.