Tris(o-tolyl)phosphine is an organophosphorus compound with the formula P(C6H4CH3)3.

It is a white, water-insoluble solid that is soluble in organic solvents.

In solution it slowly converts to the phosphine oxide.

As a phosphine ligand, it has a wide cone angle of 194°.

Complexes of this ligand are common in homogeneous catalysis.