Isothermal vapor-liquid equilibrium (VLE) data of the methanol and 2,3-dimethyl-1-butene binary system were measured at 343.06 K, 353.27 K, 363.19 K, and 372.90 K. These measurements were made with novel recirculation equilibrium stainless steel equipment. Gas chromatography was used to analyze compositions of the samples from the vapor-liquid equilibrium systems. The binary VLE data were correlated with various activity coefficient models including Wilson, NRTL, and UNIIQUAC, as well as the Soave-Redlich-Kwong equation of state.