Tris(4-methoxyphenyl)phosphine is the organophosphorus compound with the formula (CH<sub>3</sub>OC<sub>6</sub>H<sub>4</sub>)<sub>3</sub>P. Several isomers of this formula are known, but the symmetrical derivative with methoxy groups in the 4-position is most studied. The compound is used as a ligand in organometallic chemistry and homogeneous catalysis.