The stabilized conformation of the title compound, C36H25NO3, 4-(9-anthryl)-1-(2-methoxyphenyl)-spiro[azetidin-3,9'-xanthen]-2-one, may be compared with that of the isomeric compound 4-(9-anthryl)-1-(4-methoxyphenyl)spiro[azetidin-3,9'-xanthen]-2-one. In the title isomer, the methoxy group is slightly twisted out of the plane of the attached benzene ring, with a C-O-C-C torsion angle of 31.5 (2)degrees. Its beta-lactam ring is essentially planar, with a maximum deviation of -0.021 (1) angstrom. The beta-lactam ring makes dihedral angles of 18.815 (9), 83.33 (7) and 53.62 (8)degrees with the mean planes of the benzene, xanthene and anthracene ring systems, respectively. The structure is stabilized by C-H center dot center dot center dot pi, C-H center dot center dot center dot N and C-H center dot center dot center dot O interactions.