The aim of this study was to evaluate the effect of olive ripening on the oil content of olive fruit, the quality indices, fatty acid composition, sterols, waxes, o-diphenols and oxidative stability of Memecik cv. and Ayvalik cv. olive oil of organic cultivation and to determine the optimum harvesting time for these varieties. The results showed that free fatty acid content and peroxide value increase while MUFA/PUFA ratio, o-diphenols and oxidative stability decrease at more advanced stages of maturity. Statistical analysis demonstrated that fatty acid composition and sterol profile were different according to the olive variety and harvesting periods. Principal Component Analyses showed that the fatty acid composition and sterol profile of olive oils were responsible for the discrimination of olive oils obtained from different olive varieties at different ripening stages. The optimum harvesting time was found to be when the maturity index was determined as 2.09 and 2.6 for Memecik and Ayvalik varieties, respectively. Due to the growing interest in organic olive oil in national and international markets, more researches that investigate the effects of ripening, the olive variety and organic cultivation method on the quality of olive oil, are required.