Low-energy spin-wave excitations in the partially ordered ferromagnetic alloy Pd₃Fe have been studied using a Heisenberg model. A long-range order (LRO) parameter has been introduced to Murray's spin-wave theory and the order dependence of the stiffness constant to the first-order approximation is given. The nearest- and next-nearest-neighbour exchange integrals have been estimated from a neutron diffraction experiment performed by Menzinger et al (1971). The results the authors obtained are different from the values given by them.