The catalytic oxidative desulfurization (ODS) of dibenzothiophene (DBT) in decahydronaphthalene (decalin) was performed using the oil-soluble oxidant cyclohexanone peroxide (CYHPO) with a molybdenum oxide (MoO3) catalyst supported on macroporous polyacrylic cationic exchange resin D113 of weak acid series. The influence of the reaction temperature, reaction time, the molar ratio of CYHPO/DBT, and catalyst reuse was investigated in detail. In the presence of the catalyst MoO3/D113, the conversion of DBT to DBT sulfone was up to 100% at 100 degrees C in 40 min. The ODS was performed using other oil-soluble alkyl peroxides, i.e., tert-butyl hydroperoxide (TBHP) and tert-amyl hydroperoxide (TAHP), in comparison with the oxidative activity of CYHPO. The results showed that the activity of alkyl peroxides decreases in the order CYHPO > TAHP > TBHP, reversing the order of the peroxy oxygen electronic density. The oxidation mechanism is then discussed.