Mustard oil was studied by non-isothermal DSC to determine the kinetic parameters of thermal oxidation. Values of the first and second maxima of heat flow and the point of the extrapolated onset of the exothermic process obtained at different heating rates were used to calculate activation energies and Arrhenius kinetic parameters of thermal-oxidative decomposition of the oil, using the Ozawa-Flynn-Wall (OFW) method. The calculated activation energies 90.6+/-6.2 (for onset of oxidation), 88.5+/-2.8 (for first peak) and 84.6+/-1.1 kJ/mol (for second peak) were used for calculating the DSC signal. The following complex reaction models were examined : multiple reaction; competitive reaction; sequential reaction; and sequential reaction with autocatalysis start. The best fit was observed for the two-step autocatalytic reaction and the influence of the mechanism of oil autoxidation on the shape of the measured DSC signal was confirmed by this model.