Non-oxidative thermal degradation of PVC and the effect of (Ho, Tb and Dy) laurates on it was studied using thermogravimetric technique in the temperature range of 150 to 1000 degrees C. It is observed that these metal laurates effectively reduce the dehydrochlorination of PVC. The synergistic effect of combination of these salts was also studied and discussed. Kinetic parameters such as activation energy, order of reaction and Arrhenius factor have been also calculated by the Coats and Horowitz methods. Results show that above mentioned metal laurates increase the activation energy required for the dehydrochlorination of PVC.