The global essential oil market has been steadily increasing in size over the past few years, and is estimated to reach ca. $7.5 billion USD per annum by 2018. Lavenders (Lavandula; Lamiaceae) contribute significantly to this market, yielding ca. 1500 tons of essential oils which are primarily used in cosmetics, personal care products, and medicines. Recent literature indicates that these oils may also have applications in food preservation and pest control, among others. The medicinal and pharmaceutical properties of lavenders are chiefly due their essential oils, in particular the major essential oil constituents linalool and linalyl acetate, although certain activities have been attributed to the phenolic compounds. In addition, there is evidence that the major and minor essential oil constituents act synergistically to provide various biological effects. A substantial amount of current research focuses on evaluating the biological activities of lavender essential oils for potential use in traditional and complementary medicine, food systems, cosmetic and fragrance formulations, and insect control products. This review examines recent progress in these areas, and highlights the current and future implications for these economically and medicinally valuable plants.