The effect of various substituents in the benzyl moiety on the interaction between benzyltriphenylphosphonium chloride and sodium dodecyl sulfate has been investigated by conductimetric titration at a range of temperatures. Calculated functional group contributions to the thermodynamics of complexation (ΔΔGF, ΔΔHF, ΔΔSF) are considered in terms of a twofold interaction process; electrostatic interaction between charged centers reinforced by hydrophobic interaction between nonpolar functions. Enthalpy-entropy compensation effects and the interrelation of complexation and partition data are also described and discussed.