The vaporization of antimonite (Sb2S3) was investigated in the temperature range of 600-900 °C in a conventional thermogravimetric apparatus. The study was conducted in inert (N2) and oxidizing (N2-O2) atmospheres under various gas flow rates. The results indicated a linear behavior of vaporization of the sample at temperatures above 700 °C. Using the vaporization kinetic constants, activation energy of 124 kJ/mol was determined for the vaporization in nitrogen gas. On the other hand, the weight loss due to volatilization of antimonite in the presence of oxygen occurs up to a certain extent depending on the temperature and partial pressure of oxygen. 20 % of total vaporization occurred at 700 °C while at 900 °C the total vaporization was about 60 %.The incomplete volatilization of antimonite is due to the formation of non-volatile oxides since the weight loss increases with a decrease in partial pressure of oxygen.