This work presents investigations on the liquid liquid equilibria (LLE) of ternary systems composed of morpholine, acetonitrile, and an n-alkane at 298.15 K and atmospheric pressure. The investigated alkanes were n-hexane, n-heptane, and n-octane. The experimental data were compared to predictions using the perturbed chain-statistical associating fluid theory (PC-SAFT). The predictions are based on pure-component parameters fitted to vapor pressures and liquid densities as well as on binary parameters fitted to binary systems' phase equilibria. For that purpose, the vapor liquid equilibrium of the morpholine/acetonitrile system was measured at 100 mbar and modeled with PC-SAFT. Binary interaction parameters for acetonitrile/n-alkane systems were obtained from a correlation as a function of the n-alkane carbon number. This correlation, together with the other pure-component and binary parameters, was used to make predictions on ternary systems with n-alkanes longer than n-octane, for which data were taken from literature. All ternary LLE predictions were in satisfactory agreement with experimental data.