In the present work, a group contribution model is proposed for estimating the dynamic viscosity of fatty compounds. For the major components involved in the vegetable oil industry (such as fatty acids, esters and alcohols, triacylglycerols, and partial acylglycerols), the optimized parameters are reported. In order to improve the data bank gathered from the literature, viscosity data were measured as a function of temperature for three saturated and three unsaturated fatty esters, one unsaturated fatty acid, and one unsaturated triacylglycerol. These last two are unavailable data in the literature (linolenic acid and trilinolenin). A simple method of calculation is also proposed to predict the dynamic viscosity of vegetable oils as an extended applicability of our equation. The model can be a valuable tool for designing processes and equipment for the oil industry, including edible and non-edible compounds, such as biodiesel.