Viscosities of the ternary mixture (2-butanol + hexane + 1-chlorobutane) at 298.15 K and 313.15 K have been measured at atmospheric pressure. Viscosity deviations for the ternary system were fitted to Cibulka's equation. To correlate experimental data of the ternary system, extended Nissan-Grunberg and McAllister equations have been used and their parameters have been calculated. The "viscosity-thermodynamic" model (UNIMOD) has been applied first to correlate experimental data for the binary mixtures and then to predict the viscosity for the ternary system. The group-contribution thermodynamic viscosity model (GC-UNIMOD) and the group contribution method proposed by Wu have been applied to predict the viscosity for the binary and ternary systems.