A comparative analysis of the reactivities of cyclic peroxides of the substituted 1,2,4-trloxanes, 1,2,4,5-tetroxanes, and 1,2,4,5-trioxazines families of compounds was performed considering their products of reaction and kinetic data available in several media. Steric, inductive and mesomeric influence of the substituents in the thermal cleavage of the corresponding molecular rings as well the solvent effect on these unimolecular reactions was evaluated. The already known general homolytic reaction mechanism for the thermolysis in solution of the substituted tetroxanes is applicable to other representatives of the cyclic peroxides here considered. The feasibility of induced decomposition reactions by the attack of different types of molecules, intermediate free radicals or other reactive species on these cyclic peroxides as in some particular case, the cyclization processes of the corresponding biradicals in the cage of the thermolyses, were also considered. Secondary processes that mostly take place in the reactions carried out in solution were interpreted through reasonable reaction pathways. Relevant investigations performed on other cyclic peroxides with different molecular ring sizes were critically assessed to place the research work done in the field of reaction mechanisms of those type of molecules in perspective.