This study aimed to determine the quality of Lebanese olive oil by analyzing their chemical composition and their physicochemical characteristics. Olive oil samples were first collected from three different Lebanese areas. Physico-chemical investigation (acidity, peroxide index, specific extinction, total polyphenol content as well as chlorophyll and carotenoid contents) of the samples associated with fatty acid analysis by GC-MS technique and NMR characterization demonstrate the compatibility of samples with the standards of International Olive Oil Council (IOC) norms. However, obtained results showed that olive oil samples exhibited a high oxidation status, revealing the necessity of improving oil extraction procedures as well as its storage conditions. Our results confirmed further that olive crushing; harvesting as well as maturity stages have a great impact on the overall quality of obtained oil.