The present study investigates pyrolysis kinetics of raw and pretreated Goynuk oil shales by thermogravimetric analysis (TGA). Samples were treated with HCl, HNO3 and HF solutions and characterized by TGA data. All experiments were carried out at a heating rate of 5 K min(-1), in the temperature range of 25-1000 degrees C under the nitrogen atmosphere. Coats-Redfern method was used to determine the kinetic parameters of the activation energy using the data from thermogravimetric analysis. From the kinetic analysis it was concluded that Goynuk oil shale samples have two reaction regions and the activation energies of the first region are lower.