Alkyl-substituted ammonium and lithium chlorides inhibit oxygen consumption in the oxidation of styrene epoxide in the presence of p-toluenesulfonic acid in a tert-butanol-chlorobenzene (9: 1, v/v) solution at 343 K. The inhibitory effect of chlorides is the same for tetramethylammonium, benzyltriethylammonium, and lithium chlorides, thus suggesting the inhibiting action of the anion. The oxidation inhibition effect of ammonium fluoride is similar to 2.5 times as strong as that of the chlorides. The main finding of the study is the simultaneous retardation of oxidation and acid-catalyzed heterolytic epoxide consumption by the chloride and iodide anions.