Isobaric vapor-liquid equilibria (VLE) were measured for the ternary system methylbutyl ketone + nonane + cyclohexanol and for the binary methylbutyl ketone + cyclohexanol. Boiling temperature (T)-liquid composition (x) relations were obtained at (26.66, 53.33, and 79.99) kPa by using a semi-microebulliometer. The modified Wilson model was used to correlate the binary T-x data and to predict VLE in the ternary system.