Flavouring and fortifying virgin olive oils is an increasing commercial trend, aiming to meet new consumers' preferences and provide new differentiated products. These practices usually positively impact the oils’ sensory profile and chemical composition, increasing their natural richness on bioactive compounds. However, some negative effects have also been reported. This review provides a summary of common flavouring/fortification techniques as well as of the usual natural agents used. Co-extraction, contact and essential oils incorporation techniques are addressed. Usually, flavouring/fortification enhances desirable sensory sensations, and shelf-life, and promotes the incorporation of bioactive compounds like antioxidants. Also, the excess of flavouring may promote the appearance of unpleasant sensory sensations and, in some cases, results in pro-oxidant activity. Fortification, in turn, involves the incorporation of extracts rich in bioactive compounds, contributing to the nutritional and healthy enrichment of the olive oil. However, fortification may also increase the oil's turbidity and/or promote the appearance of unpleasant sensory sensations, resulting in a less appealing oil, hindering the consumers' purchasing. Although traditional in the Mediterranean, olive oil flavouring or fortification may have positive/negative effects at chemical and sensory levels. This awareness is of paramount commercial importance and can be used as a decision-maker tool for olive oil producers. Thus, the advantages/disadvantages of the different methodologies are discussed, and some perspectives and possible future directions are proposed and briefly discussed. •Olive oil flavouring is a traditional practice in the Mediterranean region.•Aromatic plants, fruits, spices and olive tree leaves are the usual flavouring agents.•Flavouring by contact and co-extraction are the most common techniques.•Flavouring and/or fortification aims to enhance the olive oil overall quality.•Positive and negative effects on the oils chemical-sensory quality are reported.