Excess enthalpies, densities, speeds of sound, and viscosities at (283.15, 298.15, and 313.15) K are reported for the binary mixture tetrahydropyran + 1-butanol. Excess molar volumes have been calculated from the densities. The deviations in both the speeds of sound and the absolute viscosities have also been estimated. All of the properties have been fit to Redlich-Kister equations.