Citrus essential oils (EOs) has been identified in different parts of fruits as well as in leaves (particularly present in fruit flavedo), showing that limonene, β-myrcene, α-pinene, p-cymene, β-pinene, terpinolene, and other elements are the major aromatic compounds of many citrus species. EOs from citrus fruits are a rich source of bio-functional compounds with various health properties, including antioxidant, antimicrobial, anti-inflammatory, and cytoprotective activities. They are mixtures of more than 200 components that can be grouped into 2 fractions which contain monoterpenes and sesquiterpenes hydrocarbons as well as their oxygenated derivatives along with aliphatic aldehydes, alcohols and esters. Today citrus fruit, juice or peel oils are currently used in everything from food or food preparations, soft drinks, ice cream, candy, pharmaceutical preparations, air fresheners, cleaning products, solvents as well as colognes and fine perfumes. This chapter will cover the production, chemistry of citrus essential oils and its applications.