This work investigates kinetics of El-Lajjun oil shale pyrolysis. The kinetic data obtained from TG/DGA curves at heating rates 1, 3, 5, 10 and 30 degrees Cmin(-1) to a final pyrolysis temperature 550 degrees C were employed assuming their second-order kinetics to determine apparent activation energy, 99-141.4 kJ/mol and frequency factor, 1.89.10(7) to 1.71.10(11), for each heating rate using the Coats & Redfern method. The obtained values of apparent activation energies and frequency factor were modified through an equation to 112-179 kJ/mol and 3.95.10(7)-3.66.10(13), respectively, to fit the developed kinetic equation. In this study, kinetic modeling of the pyrolysis process was performed using a newly developed variable reaction order. The variable reaction order was inferred directly from the experimental data and correlated with heating rate, h, (degrees Cmin(-1)), rate of conversion, (dx/dt) and a constant equal with 8.314 (degrees C). The range of generated values of the variable reaction order varied between 1.99 and 1.85. Conversion of a sample was calculated basing on initial and final weight of the sample at the end of run. A satisfactory fit of the experimental data was obtained using the equation developed for a variable reaction order.