Legume seeds, such as grass pea, yellow lupine, and narrow-leaf lupine, are highly nutritious and offer a wide range of health benefits. The objective of this research was to explore the possibility of partially replacing wheat flour (at levels of 10, 15, 20, and 25%) with flour derived from these legume seeds in sourdough wheat bread and examine its impact on the physicochemical and sensory properties of the bread. The physical properties of the dough were also assessed. The substitution of wheat flour with ground legume seeds resulted in increased water absorption (from 54.1 to 63.5%) and prolonged dough development time (from 2.0 to 13.5 min). Ground lupine seeds reduced the volume of the bread and increased its crumb density, consequently making the bread harder. The most significant increase in hardness was observed when narrow-leaf lupine flour was added to the wheat flour (from 8.4 to 22.5 N). Narrow-leaf lupine had the greatest impact on enhancing the protein content in the enriched bread (from 11.5 to 20%), while yellow lupine caused the highest increase in fiber content (from 1.9 to 6.9%). The proposed additives slightly but significantly (p < 0.05) increased the antioxidant activity and phenolic content in the bread samples. Importantly, for all legume seeds, replacing up to 15% of the wheat flour allowed the production of bread with high consumer acceptability.