The formation of mixed micelles in the surfactant cetyltrimethylammonium bromide—polyethylene glycol(∼9) monoalkanoate(∼14) binary system was shown. The stable lyomesophase involving monomers of both surfactants forms in the region of high surfactant concentrations in the temperature interval from 25 to 96 °C. In the binary micellar system, the alkaline hydrolysis of O-ethyl-O-p-nitrophenyl chloromethyl phosphonate is accelerated up to 30-fold compared with the reaction in water in the absence of a surfactant. The efficiency of catalysis depends on the molar ratio between both surfactants. The sign of the catalytic effect changes at high surfactant concentrations.