Structure. Fatty esters belong to the fatty acyls. Their structure consists of a fatty acid where the carboxyl group of the fatty acid is linked to a diverse range of substituents, including other hydrocarbon chains, via an ester bond. The chain may contain multiple double bonds and can be branched or linear, it may further feature oxygen and nitrogen containing substituents and carbon ring structures.

Function. Fatty esters are present in all living organisms, where they serve a multitude of different functions. The specific role of the fatty ester is impacted to a large extent by the composition of the hydrocarbon chain and the ester-linked substituent. For example, wax esters are a major class of storage compounds synthesized by bacteria, and make up the bulk of beeswax, carnauba wax, and candelilla wax.

Acylcarnitines (CAR) are critical to the oxidative metabolism of fatty acids and for energy metabolism. They transport free fatty acids into the mitochondria where the enzymes of β-oxidation are located. Lactones contribute to the aroma of fruits and dairy products, and are thus used as flavors and fragrances.