The nonvolatile and volatile compounds in the peels of 13 Citrus reticulata cultivars (4 mandarins, 5 tangerines, and 4 hybrids) and 5 Citrus sinensis (sweet oranges) cultivars were analyzed.Initially, 66 volatile compounds were detected using gas chromatog.-mass spectrometry (GC-MS).Tangerines were distinguished from other citrus cultivars (mandarins, sweet oranges, hybrids) by having higher volatile oil extraction rates and higher relative contents of o-Cymene, α-Terpinene, D-α-Pinene, Terpinolene, γ-Terpinene, L-β-Pinene, and 3-Thujene.Addnl., 115 nonvolatile compounds were tentatively identified using ultraperformance liquid chromatog.-Q-Exactive Orbitrap tandem mass spectrometry (UPLC-Q-Exactive Orbitrap-MS).C. sinensis contained fewer compounds than did C. reticulata.Pterostilbene was detected in all tangerines but not in mandarins and hybrids, suggesting its potential as a marker compound for differentiating tangerines from other C. reticulata.Lastly, a high-performance liquid chromatog.-photodiode array (HPLC-PDA) was used to quantify 9 major nonvolatile components.Heat map and principal component anal. showed that the contents of tangerines differed from other cultivars (sweet oranges, mandarins, and hybrids).It may be caused by the higher content of synephrine, nobiletin, tangeretin, and 5-hydroxy-6,7,8,3′,4′-pentamethoxyflavone in tangerines.The study may obtain information for the application of different types of C. reticulata (tangerines, mandarins, or hybrids) and C. sinensis peels, thereby promoting their recycling.