In the title compound, C20H20NOP, the P atom, with a distorted tetrahedral geometry, is attached to an O atom, two phenyl groups, and a 3,5-dimethylaniline group. The N—P—C [102.29 (12) and 108.97 (12)] and C—P—C [107.14 (12)] bond angles are all smaller than the ideal 109.5 tetrahedral bond angle, whereas the O—P—C [113.07 (12) and 110.62 (12)] and O—P—N [114.24 (13)] angles are all larger than 109.5. A weak intramolecular C— HO hydrogen bond helps to establish the molecular conformation. In the crystal, the molecules are linked by N—HO hydrogen bonds, generating [001] chains.