Effect of non-catalytic aqueous pretretment on pyrolysis characteristics of Napier grass was investigated using thermogravimetric analyser. Increasing pretreatment severity (0.0-2.0) improved pyrolysis process. The residual mass at the end of pyrolysis for the pretreated sample was about 50 less compared to the untreated sample. Kinetics of the process was evaluated using order based model and both pretreated and untreated samples followed first order reaction. The activation energy of the pretreated samples was similar and higher than that of the raw sample which was attributed to faster rate of decomposition due removal of hetromaterials (ash, extractives and some hemicellulose) in the pretreatment stage. Finally, this pretreatment method has demonstrated effectiveness for the removal pyrolysis retardants and will improve the quantity and quality of bio-oil yield. © School of Engineering, Taylor�s University.