We report a squaramide-catalyzed aza-Michael/Michael cyclization of nitroalkenes with 3-benzoylacylamides, facilitating the asymmetric synthesis of γ-lactams. This method efficiently generates a range of optically pure γ-lactams, in yields ranging from 25% to 90% and enantioselectivities exceeding 99%. Performed under mild conditions, this method highlights the significance of γ-lactams as versatile scaffolds in drug discovery, showcasing the high stereocontrol and adaptability of this synthetic strategy.