The total vapor pressure of gallium dichloride was determined by the torsion method over the temperature range of (372 to 441) K, and its temperature dependence was represented by the equation log(p/Pa) = (14.23 +/- 0.30) - (5829 +/- 00)/(T/K). From this equation the second-law sublimation enthalpy of a mole of gaseous mixture was derived as Delta(sub)H degrees (406 K) = (111 +/- 2) kJ.mol(-1).