A critical model of water-oil surfactant distribution has been developed and validated for the evaluation of mixed surfactant partitioning and distribution in water-oil environments. The surfactant distribution model, which is a combination of surfactant partitioning sub-model, partitioning coefficient calculation method, and a developed critical micelle concentration (cmc) prediction sub-model based on previous work, provides a very powerful tool to evaluate the partitioning of mixed surfactants in water-oil environments. Different methods to calculate partitioning coefficients are introduced, which includes transfer free energy method and group contribution method. The partitioning data from model prediction and from experiment agree very well. The mixed micelles start to form in water-oil environments only after the apparent cmc is reached during partitioning. The selective partitioning of one particular surfactant in mixed surfactants can be explained-by its apparent cmc which is interpreted as one characteristic of the hydrophobicity/hydrophilicity of that surfactant in water-oil environments. It is believed that the partitioning and distribution of non-homologous mixed surfactants in oil-water environments are evaluated theoretically and experimentally for the first time. The effect of partitioning on corrosion inhibition of mixed surfactants was initially evaluated by modified Langmuir adsorption and by electrochemical measurements. The corrosion inhibition efficiency from model prediction and, from experimental measurements is comparable. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.