In this study, the development and validation of a simplified nonlinear dynamic model of a passive twin-tube hydraulic shock absorber is presented. First, the experimental dynamic response is characterized. Then, the numerical model is presented where flow, pressure, displacement, and velocity are considered. Finally, the numerical–experimental correlation is performed on force-movement dynamic behavior to prove the accuracy of the proposed model. The final goal of the model is to be integrated in a real-time driving simulator for ride comfort studies.