The total pressure and vapor and liquid compositions have been measured for N-methyl-2-pyrrolidone + benzene at 330.00 K and 350.00 K, for N-methyl-2-pyrrolidine + toluene at 343.15 K and 373.15 K, for N-methyl-2-pyrrolidone + heptane at 340.00 K and 365.00 K, and for N-methyl-2-pyrrolidone + methylcyclohexane at 340.00 K and 370.00 K. Measurements were made by either a recirculating still or a transpiration method, the method depending on the total pressure of the mixture. The results were correlated using the Redlieh-Kister equation, the Wilson equation, and the NRTL equation, with allowance for vapor nonideality.