Excess molar volumes of (butan-1-ol, or butan-2-ol, or 2-methylpropan-1-ol, or 2-methylpropan-2-ol + benzene, or toluene) over the entire range of composition have been measured dilatometrically at the temperature 308.15 K. The results indicate that the branching of an alkyl group of butanol near the hydroxyl group makes both the hydrogen bonding and the electron donor-acceptor interactions between butanol and benzene or toluene molecules less effective.