The prediction of fretting wear and fretting fatigue is a significant issue for the design of high-performance aeroengine spline couplings, due to the potential for slip between the highlyloaded spline teeth under cyclic loads. The work reported here builds on previous work on simpler (Hertzian) laboratory test configurations to take a step towards a unified fretting wear and fatigue modelling approach, which considers the evolution of contact geometry with material removal and consequently the changes in fatigue-pertinent subsurface stresses. The approach calculates the local wear, that it is the wear at each contact node, as a function of local contact pressure and local slip. The influence of wear damage on fretting fatigue behaviour is quantitatively assessed by computing the change of a shear strain based fatigue damage parameter, i.e. the critical-plane Fatemi-Socie parameter. The application of the simulation tool to the complex geometry of a helical spline coupling is discussed.