Antioxidant capacity, nutritional and functional quality of wheat bread supplemented with 1–5% flaxseed hull (FH) were studied. Analyses of the chemically-extractable fraction show that supplementation with 5% of FH increased (compared to control) phenolics content (by 93%), radicals scavenging ability (by 176%) and reducing power (by 220%). Furthermore, phenolic antioxidants were bioaccessible in vitro (samples after simulated digestion). Fortification had no significant influence on rapidly and slowly digestible starch, in vitro starch digestibility and values of expected glycemic index; however, a decrease (up to 8%) of relative proteins digestibility was determined. Enrichment decreased loaf volume and increased crumb hardness. The results from sensory evaluation show that the incorporation of FH had a slightly unfavorable effect on bread sensory properties but ensured satisfactory consumer acceptability. In view of these facts, it is concluded that flaxseed hulls may be a beneficial food additive.