Allylic oxidations of olefins to enones are C–H functionalizations and are valuable organic transformations that permit the synthesis of value-added products from simple precursors. A variety of stoichiometric and catalytic metal-based methods are available for these conversions. In addition, metal-free and biocatalytic protocols are gaining in importance. This review summarizes the available oxidation methods and compares their regio- and chemoselectivities. 1 Introduction 2 Chromium-Based Oxidation 2.1 Stoichiometric Methods 2.2 Catalytic Methods 2.3 Chromium on Solid Support 3 Regio- and Chemoselectivity of Allylic Oxidations 4 Other Metal-Based Oxidations 4.1 Copper Reagents 4.2 Rhodium Reagents 4.3 Selenium Reagents 4.4 Cobalt Reagents 4.5 Ruthenium Reagents 4.6 Palladium Reagents 4.7 Iron Reagents 4.8 Other Metal Reagents 5 Metal-Free and Biocatalytic Methods 5.1 Metal-Free Methods 5.2 Biocatalytic Methods 6 Conclusion