A quantitative measurement of degree of deacetylation of Sterculia urens gum and its effect on the thermal properties changes is presented in this study. Sterculia urens gum was deacetylated at varying deacetylation reaction temperature and time. The acetyl group is replaced by hydroxyl which leads to better solubility of the sterculia gum in water. Thermal properties were characterized using differential scanning calorimetry and thermogravimetric analysis. DSC analysis reveals that after the deacetylation, the glass transition temperature appears at around 60 °C of the S. urens gum. After deacetylation, the TG degradation clearly shows three different peaks. Deacetylation reaction temperature plays the major role in the thermal stability and structure of the S. urens gum.