This study aimed to investigate the effect of fish skin gelatin (Gadus morhua, 0.5%, or 1.0%, flour basis) on the properties of wheat (Triticum aestivum) dough and bread. Compared with the control group, the addition of 1.0% gelatin increased the storage modulus and the maximum resistance of dough, resulting in a longer rupture time and a larger final gas-retention volume of the dough. Bread characteristics showed that the specific loaf volume and crumb cell size both increased. Molecular dynamics simulation indicated that gelatin and glutenin segments formed a complex, where a large amount of hydroxyl groups on the surface retarded water mobility in bread. Gelatin-glutentin complexes with the high water-holding capacity inhibited water diffusion from marginal crumb to crust, and decreased starch retrogradation enthalpy and firming rate of crumb. Thus, fish skin gelatin might be a good improver of wheat dough and bread.