Jeroen S.W. Lamb and F. Wijnands: From multi-site to on-site transfer matrix models for selfsimilar chains Abstract: We show how transfer matrix models on chains that are selfsimilar (renormalizable) with respect to a substitution rule can be transformed from multi-site models in which transfer matrices depend on the nature of a finite number of neighbouring sites, to on-site models in which transfer matrices depend on the nature of one site only. We present sufficient conditions and show that these conditions are satisfied in the case of quasiperiodic chains of two symbols that are renormalizable with respect to an invertible substitution rule. We illustrate the application of our results to tight binding Schr\"odinger equations modeling the electronic behaviour of selfsimilar chains of atoms and to models describing the transmission of light through selfsimilarly stacked multilayers.