A series of experiments was performed to measure the interfacial tension of organic solvent/aqueous solutions of binary blends of suspension-agent systems. The experimental data was modeled with the nonideal adsorbed solution (NAS) model developed by Siddiqui and Franses, which considers interactions between the suspension agents. The interaction parameters of the model were estimated with a custom-designed numerical algorithm. The estimated interaction parameters reflect the differences in chemical structure of the blends of suspension agents. The NAS model accurately represents the effect of blends of suspension agents in different ratios and total concentrations on the interfacial tension. It was shown how Langmuir isotherms and the NAS model can be used to interpret and understand the behavior of organic solvents/water suspensions protected by suspension agents in combination with a surface-active-agent mass balance, how blends of suspension agents interact in the interface, and the effects of such interactions.