The pseudo-binary model developed by Wu and Asfour (1992) has been used to modify some existing viscosity predictive models to that they can predict the viscosities of multicomponent liquid n-alkane and regular mixtures. The n-alkane three-body interaction model and the Grunberg-Nissan viscosity equation were both employed, after modification, to successfully predict the viscosity of multicomponent liquid n-alkane and regular solutions. The modified Generalized Corresponding States Principel (MGCSP) reported by Wu and Asfour (1992), for only predicting the viscosities of n-alkane mixtures, has been extended to predit the viscosities of multicomponent regular solutions. The predictive capabilities of several predictive models were analyzed. The obtained results showed that the pseudo-binary McAllister model predicts the viscosity data better than the other existing predictive models.