In chemistry a phosphine imide (sometimes abbreviated to phosphinimide) also known as a iminophosphorane is a functional group with the formula R₃P=NR. While structurally related to phosphine oxide its chemistry has more in common with phosphonium ylides.

Anions of this group, with the structure R₃P=N⁻, are called phosphinoimidates and are used as ligands to form phosphinimide complexes which are highly active catalysts in some olefin polymerization reactions.

Phosphine imides can be isolated as intermediates in the Staudinger reaction and have also been prepared by the action of hydroxylamine-O-sulfonic acid on phosphines, proceeding via a p-aminophosphonium salt.

The functional group will readily hydrolyse to give a phosphine oxide and an amine

Phosphinimide ligands of the general formula NPR₃⁻ form transition metal phosphinimide complexes. Some of these complexes are potential catalysts for the synthesis of polyethylene.