In this study, the kerogen types of Goynuk, Beypazari oil shale from Turkey and Timahdit oil shale from Morocco were defined by infrared spectroscopy. Aliphatic, carboxyl/carbonyl and aromatic compounds were considered in order to classify the kerogen types. The IR-analysis result shows that the samples can be classified in kerogen evaluation path I for Goynuk. Timahdit oil shales and path II for Beypazari oil shale. The kinetics of thermal decomposition of Goynuk Beypazari and Timahdit oil shales have been studied by non-isothermal thermogravimetry (TG). The weight loss data have been analyzed by Coats-Redfern and Chen-Nuttall combinations. The kinetic parameters for the decomposition of the samples were determined and discussed.