The olive oil composition of eleven cultivars (cvs. Arbequina, Arbosana, Arroniz, Cornicabra, Frantoio, Hojiblanca, Manzanilla, Picual, Picudo, Redondilla and Royuela) cultivated in a high-density olive grove located in a non-traditional producing region (Valladolid, Spain) was studied during four consecutive crop seasons. The results showed that the 122 monovarietal olive oils studied could be classified as extra virgin oils, according to the quality parameters. Furthermore, the olive cultivar had a marked effect on the chemical composition and antioxidant activity. In general, olive oils from cvs. Picual and Cornicabra showed the highest total phenolic contents, oxidative stability, and tocopherols contents, whereas the worst results for oxidative stability were observed for cv. Redondilla olive oils, probably associated to the lowest contents of phenolics and tocopherols and the highest amounts of polyunsaturated fatty acids. Finally, it was found that, despite the different crop years evaluated, the quality-chemical profiles could be used to successfully discriminate the monovarietal oils under study (linear discriminant analysis sensitivities: 92 ± 5% for the repeated K-fold cross-validation), using the data of 15 non-redundant variables identified by the simulated annealing variable selection algorithm.