Isothermal vapor-liquid equilibrium of binary systems of tetrahydrothiophene + n-butane, + trans-2-butene, + 2-methylpropane, and + 2-methylpropene was measured at (318 and 346) K or 347 K with a static total pressure apparatus. The measured data were reduced to phase equilibrium data with the Barker's method. Legendre, Wilson, NRTL, and UNIQUAC parameters were calculated. All binaries exhibited a positive deviation from the Raoult's Law. No azeotropes were observed.