In the paper titled "Key performance indicators reveal the impact of demulsifier characteristics on oil sands froth treatment" by Ishpinder Kailey, [Kailey, I. Key performance indicators reveal the impact of demulsifier characteristics on oil sands froth treatment. Energy Fuels 2017, 31, 2636-2642] the author emphasized the importance of interfacial tension (IFT) and relative solubility number (RSN) on the performance of demulsifiers in the oil sand froth treatment. However, the IFT data analyses were incorrect, which led to wrong conclusions. The reason why demulsifier performance is related to RSN was not explained. In addition, the paper has issues with the experimental method and literature citation.