Densities (Q), refractive indices (n), absolute viscosities (eta), and static dielectric constants (epsilon) have been measured over the entire range of composition for binary mixtures of 2-methylpropan-2-ol with hexane, benzene, propan-2-ol, methanol, ethanol, and water at 303.2 K. Excess molar volumes were fitted to Redlich-Kister equations.