A limiting factor impacting the quality and recovery of bitumen from oil sand operations is the formation of stable water-in-oil (w/o) and/or oil-in-water (o/w) emulsions during froth treatment. In a previous study, the impact of asphaltene partitioning on oil-water phase separation from the resulting emulsified phases (rag layers) was evaluated as a function of the solvent bitumen water ratio, temperature, and solvent aromaticity. In this work, the added effect of naphthenic amphiphiles at concentrations of 3 and 10 wt % on oil water phase separation from similarly formulated rag layers is assessed. The observed phase behavior of these rag layers is discussed in view of interfacial coadsorption mechanisms proposed in the literature. A major finding is that, under alkaline process conditions, an increase in the concentration of sodium naphthenates (NaNs), produced as a result of naphthenic amphiphile dissociation, promotes a shift in emulsion morphology from w/o to o/w. The resulting transition from asphaltene-to NaN-controlled properties significantly limits oil water phase separation as a result of an increase in the surface area to volume ratio of dispersed droplets and an enhancement of interfacial asphaltene partitioning. Contrary to NaN-free systems, it was also observed that both the temperature and solvent aromaticity have a minimal effect on the phase behavior of NaN formulations. Furthermore, undissociated naphthenic amphiphiles, referred to as naphthenic acids, are capable of promoting oil water phase separation under acidic formulation conditions.