Vapor-liquid equilibrium at 94 kPa has been determined for the binary system oxolane + octane and methyl 1,1-dimethylethyl ether + hex-1-ene. The system oxolane + octane deviates strongly from ideality with no azeotrope formation. The system methyl 1,1-dimethylethyl ether + hex-1-ene presents ideal behavior. The activity coefficients of the system oxolane + octane were correlated reasonable well with its composition by the Redlich-Kister, Wohl, Wilson, UNIQUAC, and NRTL models. The boiling point of both binary systems were correlated with the Wisniak-Tamir equation.