New isothermal vapor-liquid equilibrium (VLE) and vapor-liquid-liquid equilibrium data for the carbon dioxide + 1-octanol system are reported at several temperatures, 303.15, 310.15, 315.15, 323.15, and 333.15 K, and pressures up to 145 bar. A static analytical method with phase sampling was used. The experimental results of this study are compared with literature data when available and discussed. The new and all available literature data for the carbon dioxide +1-octanol binary system are modeled with the cubic general equation of state and Peng-Robinson equations of state (EoS) with classical van der Waals mixing rules. The aforementioned EoS's were used to model the phase behavior of the carbon dioxide + 1-octanol binary system (critical curves, the three-phase equilibrium curve, isothermal VLE, and vapor-liquid-liquid equilibria), using a semipredictive approach. The results of the calculations are compared to the new data reported in this work and to all available literature data. The results show a satisfactory level of agreement between the models and the experimental data.