Hydrazones are described as synthetic equivalents to the carbonyl group and possess high synthon value. Herein, we compile the oxidative transformation of hydrazones using ecologically and economically benign hypervalent iodine reagents of the last decade. In this field, the development of C─H functionalization reactions leading to the formation of heterocycles or functionalized hydrazones is a major advancement in recent years. The oxidative properties of hypervalent iodine reagents are exploited to form many bioactive heterocycles (pyrazole, pyrazoline, pyridazine, 1,2,4‐triazole, 1,2,3‐tiazole, 1,3,4‐oxadiazole, tetrazine, tetrazole, pyrrole) through intramolecular or intermolecular C─N, C─O, or N─N coupling. Functionalized heterocycles are also afforded via tandem cascade group transfer/cyclization reactions. The transfer of perfluoroalkyl, sulfoximidoyl, aryl, and halogen groups is achieved using hypervalent iodine reagents as group donors or oxidants in combination with other group‐donating agents. The Togni reagent is the preferred choice for trifluoromethyl group donation, with or without a metal catalyst. Moreover, rearrangement reactions such as acyl migration and the diazotization of hydrazones are also achieved.