Foliage and soil-applied boron (B) can potentially boost the nutritional quality of maize; however, research gaps exist regarding B dose optimization for maize in the Mediterranean environment. A trial was performed at the Agronomic Research Area, Hatay (Mediterranean region), Turkey, during the autumn seasons of 2018 and 2019 to investigate the effect of basal and foliage B fertilization on the nutrient contents of maize grains. Di-sodium octaborax tetrahydrate (Na2B8O13.4H2O) was used as a source of boron. The experiment consisted of five levels of soil-applied boron (0, 3000, 6000, 9000, and 12000 g ha-1), which were subjected in the main plots, and three levels of foliar-applied boron (0, 3000, 6000 g ha-1), which were assigned in the sub-plots. Ears were harvested and randomly selected for analysis of protein, starch, fat, and mineral elements of maize grain. The quality traits of maize grain were significantly influenced by different levels of B. The maximum nutritional quality traits were recorded for the treatment of soil-applied B (9000 g ha-1). The soil-applied B (9000 g ha-1) and foliar spray (3000 g ha-1 B) significantly improved the quality traits of maize, especially starch, P, K, Ca, B, Cu, and Fe content. Hence, soil and foliar application of B could be considered an effective approach for achieving maize grain of higher nutritional quality under Mediterranean agro-climatic conditions.