Moringa oleifera seed protein hydrolysates exhibit good hypoglycemic activity, but their specific peptide components have not yet been characterized. Here, we identified the ultrafiltration peptide components (<3 kDa) of M. oleifera seed protein hydrolysates. A highly active α-glucosidase inhibitory peptide with an IC50 value of 109.65 μM (MoHpP-2) with the amino acid sequence KETTTIVR was identified. We characterized its structural properties, stability, and hypoglycemic activity. MoHpP-2 was found to be an amphipathic peptide with a β-turn structure, and the hemolysis of red blood cells was not observed when its concentration was lower than 2 mg mL-1. MoHpP-2 was stable under weakly acidic conditions, at temperatures lower than 60 °C, and at high ion concentrations. Western blotting revealed that MoHpP-2 affected the PI3K and AMPK pathways of HepG2 cells. Molecular docking revealed that MoHpP-2 interacted with α-glucosidase through hydrogen bonding and hydrophobic forces. Thus, MoHpP-2 from M. oleifera seeds could be used to make hypoglycemic functional foods.