Vapor-liquid equilibrium data in the three binary 2-methylpentane + 3-methyl-2-butanone, 2-methylpentane + 3-methyl-2-butanol, and 3-methyl-2-butanone + 3-methyl-2-butanol systems and in the ternary 2-methylpentane + 3-methyl-2-butanone + 3-methyl-2-butanol system are reported. The data were measured isothermally at (330.00 and 340.00) K covering the pressure range (9 to 100) kPa. The binary vapor-liquid equilibrium data were correlated using the Wilson, NRTL, and Redlich-Mster equations; resulting parameters were then used for calculation of phase behavior in the ternary system and for subsequent comparison with experimental data.