A detailed linear and nonlinear analysis of void wave phenomena in two-phase flow is presented. A state-of-the-art, one-dimensional two-fluid model was used as the basis for this analysis. It is shown that void wave dispersion is strongly influenced by phasic slip. In particular, the smaller the slip the more dispersion occurs. It has also been found that nonlinear wave forms, such as shocks and solitons, may occur. Moreover, the virtual mass force was found to be an important parameter in the modeling of void waves. It is shown that void wave analysis is an excellent means of assessing the closure assumptions used in two-fluid models. It is also implied that carefully taken void wave data are needed for this purpose.