In the title compound, C18H16N2O2S, the 5-dihydroisoxazol-5-yl ring and its phenyl substituent are nearly coplanar, with the largest deviation from the mean plane being 0.0184 (16) Å. The thiomorpholin-3-one ring adopts a screw-boat conformation and the attached benzene ring makes a dihedral angle of 42.26 (7)° with the mean plane through the 3-phenyl-4,5-dihydroisoxazol-5-yl ring system. In the crystal, molecules are linked by pairs of C—H...N hydrogen bonds, forming inversion dimers. These dimers are linkedviaC—H...O hydrogen bonds, generating a three-dimensional network.