The effects of jet milling and air classification techniques on rice bran fractions and consequently on bread processing quality were investigated in this study. Rice bran coarse (RBC) and fine (RBF) fractions were obtained from defatted rice bran (RB) through jet milling and air classification techniques and changes in their nutritional composition and particle size distribution were systematically examined. Overall, their compositional profiles were altered upon treatment. The dietary fiber content in RBC was increased, and protein and phytic acid contents were reduced, whereas opposite trends were observed in RBF. Significant reductions in average particle size were achieved in both the RBC and RBF groups, decreasing by 37.06% and 97.34%, respectively, whereas particle size uniformity was improved. Compared with the RB group, RBC addition was found to extend dough stability time, enhance both the elastic (G′) and viscous (G″) moduli of dough, and improve bread processing quality. These improvements manifested as a 46.05% increase in specific loaf volume and 15.12% reduction in crumb hardness. In contrast, finer RBF particles exhibited opposite effects-deteriorating flour farinograph characteristics and dough rheological properties while weakening bread quality attributes. Compared with the RB group, RBF the smaller particle size of RBF promoted gluten protein depolymerization more effectively, as evidenced by a 23.94% decrease in glutenin macropolymer content and 42.13% increase in free sulfhydryl groups. RBC showed no significant effect on these parameters. In summary, RBC was identified as an effective modification to mitigate the negative effects of RB incorporation in bread production. These findings provide technical support for expanding RB applications in baked products.