Phenolic compounds are a diverse range of secondary metabolites derived from the shikimate pathway and phenylpropanoid metabolism. Olea europaea L. contains a number of unusual phenolics including various oleosides. The amounts and types of phenolics vary markedly between leaf, fruit, stone, and seed. The metabolic relationships between the various parts and phenolic content are poorly understood. Interest in this area is related to the importance of the phenolic profile to the aesthetics and quality of olive products, and to the use of olive leaves in phytomedicines.