The central -lactam ring of the title compound, C23H21NO3, is almost planar (r.m.s. deviation = 0.032Å). The methoxybenzene ring is almost coplanar with the -lactam ring [dihedral angle = 1.87 (11)°], whereas the tolyl ring is almost normal to it [75.73 (12)°]. The dihedral angle between the -lactam ring and the O-bonded phenyl ring is 51.95 (12)°. An intramolecular C-HO interaction generates an S(6) ring. The crystal structure features intermolecular C-HO hydrogen bonds, forming layers parallel to (011), and weak C-H interactions. Two aromatic - stacking interactions [centroid-centroid distances = 3.6744 (12) and 3.6799 (11) Å] are also observed.