AbstractA study of the relaxation kinetics in the partially inverse NiAl2O4 spinel after temperature jumps T1 T2 is reported. The change of the lattice parameter was measured by high temperature X‐ray diffraction at T2 (695–760°C) using NiAl2O4 powder samples equilibrated with NiO in air. For the temperature range of T1 under study (1100–1450°C), the kinetics can be well described by an equation which is formally equivalent to a third‐order rate law. Changes of the diffraction line widths occur during the relaxation which are due to elastic stresses, strongly dependent on the initial temperature T1. Comparison with recent results from optical spectroscopy indicates that the process observed by lattice parameter measurements is not the homogeneous exchange reaction between the two cation sublattices. The nature of the various relaxation phenomena occurring on different time scales is discussed taking concentration inhomogeneities of structure elements and elastic stress fields on different length scales into account.