High-temperature mass spectrometric studies on xMnO + (1 -x)TeO2 samples with x = 0.50, 0.54, 0.57, 0.67, 0.75, and 0.79 were conducted to investigate the vaporization behavior of the MnO-TeO2 binary system. Along with MnTeO3, a phase of equimolar composition, another ternary phase Mn3TeO6 lying on the oxygen-rich side of the MnO-TeO2 binary line was generated during preparations as well as during isothermal dynamic effusion experiments, Experiments were also conducted by adding a known excess of MnO or Mn to aliquots from different samples to examine whether the resulting condensed phase-vapor phase equilibrium would preclude or at least retard the buildup of Mn3TeO6 On the contrary. these experiments, many being characterized by high Te-2(g) evolution in the initial stages, yielded residues of MnTeO3 + Mn3TeO6 or Mn3O4 + Mn3TeO6 the latter when the MnO addition was such that the resulting overall x(MnO) was as high as 0.80. The vapor phase in all cases consisted only of Te- and O-bearing species: TeO2, TeO, Te-2, and O-2. These observations led to the inference that the MnO-rich region of the MnO + TeO2 system is not inclined to remain binary during vaporization. Anomalous vaporization behavior was observed for Te-2(g) in some isothermal experiments. While for all other gaseous species monotonic decrease in partial pressures ended with values stabilizing around the respective minimum. that in the p(Te-2) ended with a turn-around in its value; there was a rapid increase to eventually stabilize at a value that was not only about four times higher than the minimum but also even higher than that measured before the onset of monotonic decrease. These features and other aspects associated with different univariant vaporization equilibria in the Mn-Te-O ternary system are discussed.