The standard sublimation enthalpies of simetryn (N,N '-diethyl-6-(methylthio)-2,4-diamine-1,3,5-triazine), ametryn (N-ethyl-N '-(1-methylethyl)-6-(methylthio)-2,4-diamine-1,3,5-triazine), and terbutryn (N-(1,1-dimethylethyl)-N '-ethyl-6-(methylthio)-2,4-diamine -1,3,5-triazine) were determined by nonisothermal differential scanning calorimetry and nonisothermal and isothermal thermogravimetry, both techniques based on the Langmuir equation. For simetryn, ametryn, and terbutryn, the sublimation enthalpy values Delta H-sub degrees(298 K) = {(117 +/- 5), (121 +/- 5), and (112 +/- 5)} kJ.mol(-1), respectively, were selected from nonisothermal and isothermal thermogravimetry data. The temperature dependence of the vapor pressures was selected from isothermal thermogravimetry data for the examined compounds: ln(p/kPa) = (23.86 +/- 0.38) - (10410 +/- 160)/(T/K) (from (391.4 to 456.0) K), In (p/kPa) (23.30 +/- 0.44) - (10458 +/- 189)/(T/K) (from (400.1 to 470.6) K), and ln(p/kPa) = (21.80 +/- 0.41) - (9978 +/- 178)/ (T/K) (from (402.8 to 464.3) K) for liquid simetryn, ametryn, and terbutryn, respectively. From the isothermal thermogravimetry data, the standard sublimation entropies for simetryn, ametryn, and terbutryn equal to Delta S-sub degrees(298 K) = {(243), (244), and (214)} J.K.mol(-1), respectively, were derived with an estimated uncertainty of 10 J.K.(-1). mol(-1) for all the studied triazines.