<p>Viscosity is one of the most crucial parameters to understand the characteristics of the flow of liquid. Several processes, such as casting, hot dip coating, <i>etc.</i>, require knowledge of the viscosity of the liquid alloy to enhance the efficiency and quality of the process and product. However, accurate measurement of the viscosity of liquid metal is extremely challenging due to reasons such as high temperature, oxidation of elements, vapour pressure of volatile elements, <i>etc.</i> Thus, a model to predict the viscosity of a multicomponent alloy system is of utmost importance. In the present study, a Viscosity model of multicomponent system was developed by combining the Seetharaman Du-Sichen (SDS), Kaptay and Associate model with the CALPHAD methodology. Viscosity of Al–Si, Al–Mg, Al–Fe and Al–Si–Mg systems were estimated. The calculated viscosities were corroborated with existing experimental data. SDS model combined with CALPHAD found to predict viscosity in Al–Si and Al–Mg and Al–Si–Mg alloy system. Kaptay model combined with CALPHAD was able to predict viscosity in Al–Fe system with moderate accuracy. However, Associate model was able to predict viscosity in Al–Fe system with high accuracy. Elements such as Si and Mg are found to decrease the viscosity of the Al-rich alloys. However, Fe is found to increase the viscosity of the alloy.</p>