A unified approach toward modeling fuel sprays for internal combustion engines is presented in this work. The fuel injection process has been divided in three subprocesses, namely, primary atomization, drop deformation and aerodynamic drag, and secondary atomization. Two different models have been used for the primary atomization, depending on whether a high-pressure swirl atomizer or a multihole nozzle is used. The drop deformation and secondary atomization have been modeled based on the physical properties of the system, independent of the way the droplets were created. The secondary atomization has been further divided into four breakup regimes, based on experimental observations reported in the literature. The model has been validated using a wide array of experimental conditions, ranging from gasoline to diesel sprays, in nonevaporating conditions. Overall, the model performs well, predicting correct trends for the spray characteristics, without the need for recalibration.