This review is devoted to the analysis of the kinetics of S(IV) (sulfite and bisulfite ions) oxidation by molecular oxygen, ozone, hydrogen peroxide, and peroxymonosulfate in aqueous solutions. Much attention is given to S(IV) oxidation by oxygen. On the basis of the analysis performed, the most reliable rate constants of the reactions involved in the chain-radical process are selected. The ion-molecular mechanism of S(IV) oxidation by H2O2 is considered. This mechanism is shown to closely resemble that of S(IV) oxidation by peroxymonosulfate. Analysis of sulfite oxidation by ozone leads to the conclusion that, in spite of a great number of studies, the mechanism of this reaction remains unclear.