Modeling of reactive sputter deposition processes is a very important tool for fast and inventive process development. A short review with some new results is given for a set of previously presented reactive sputtering models that has been successful in describing and predicting the processes. Examples are given for each case of reactive sputtering with one target and one reactive gas, reactive compound- and co-sputtering as well as reactive sputtering using two reactive gases. The importance of process control in order to control the inherent instabilities and composition, is emphasized.