The standard molar Gibbs energy of formation of barium tellurite, BaTeO3(s), was determined by the transpiration technique using pure oxygen as the carrier gas in the temperature range 1133 K to 1260 K. The condensate was exclusively identified as TeO2 (s) by chemical analysis. From a quantitative chemical analysis of the condensed TeO2(S), the vapour pressure of TeO2(g) over pure BaTeO3(s) was calculated and is given by ln{p(TeO2, g)/kPa +/-0.1} = 18.64 - 30863.2. (.) (K/T). The Gibbs energy of formation of BaTeO3(s) was computed from the values of ln{p(TeO2, g)/kPa} and the values of Delta(f)G(m)(O) for BaO(s) and TeO2(g) taken from the literature and is given by {Delta(f)G(m)(O) (BaTeO3, m In s, T)/kJ (.) mol(-1) +/- 1.0} = -856.5 + 0.2067 - (T/K). The enthalpy increments of BaTeO3(s) were measured using a high-temperature Calvet micro-calorimeter in the temperature range 304 K to 1000 K. Enthalpy increment values are represented by a polynomial of the form {H-O(T) - H-O(298.15 K)}/(J (.) mol(-1)) = -39 190 + 118.96. (T/K) + 4.235.10(-3) (.) (T/K)(2) + 9.975 (.) 10(5) (.) (K / T), with an accuracy of 0.4 per cent over the interval (304 less than or equal to T/K less than or equal to 1000).