One of the possible ways to optimize the productive performance of poultry is through the physical processing of ingredients, which can improve the use of nutrients in these animals. In this context, this study was to evaluate the effects of different corn particle sizes in diets on the productive performance and egg quality of semi-heavy laying hens. Sixty naked neck laying hens were used from 24 weeks of age and distributed in a completely randomized design. Experimental diets in different treatments contained corn grain ground into sieves with a diameter of 2, 4, or 8 mm to provide corn particles with a geometric mean diameter (GMD) of 605 (fine), 1,030 (medium), and 2,280 μm (coarse), respectively. The feed and leftovers were weighed daily throughout the experimental period to determine the feed intake and feed conversion. Different corn particle sizes did not affect any aspect of the productive performance of hens, except for feed intake. Hens fed fine and medium corn particles exhibited higher values for egg yolk color, eggshell weight, and eggshell thickness. It is suggested that semi-heavy laying hens should be fed mash diets containing corn particles with GMD from 605 to 1,030 μm, because coarse corn particles cause a negative effect on eggshell quality.