A density functional theory study was performed on the Baeyer-Villiger reaction of bicyclo[4.2.0]octan-7-one and bicyclo[3.2.0]heptan-6-one with hydrogen peroxide. The thermodynamic and kinetic parameters were analyzed by considering the regio-isomeric Pathways, we found that the regioisomers P1 and P3 are kinetically and thermodynamically favored.