Liquid–liquid equilibria of water + formic acid + dimethyl carbonate have experimentally been specified at (298.2, 308.2, and 318.2) K. Each phase diagram was obtained by specifying binodal curves and tie-lines. The reliability of the experimental tie-lines was verified via the Othmer–Tobias correlation. The experimental tie-line data were correlated using the nonrandom two liquid and the universal quasichemical (UNIQUAC) models in order to obtain the binary interaction parameters. However, UNIQUAC functional-group activity coefficients (UNIFAC) and modified-UNIFAC methods were also used to predict the phase equilibrium in the system determined from experimental data using the interaction parameters between CH3, OCOO, HCOOH, and H2O functional groups. Distribution coefficients and separation factors were evaluated for the immiscibility region.