Terpenes represent a diverse group of natural substances that probably have the most structural representatives in the biochemical world. This chapter explains the basic biosynthesis of key metabolites via the mevalonate pathway and how it has been genetically optimized. After clarifying the taxonomy of terpenes, their individual groups such as mono-, di-, tri-, tetra-, and polyterpenes are discussed in detail with technically relevant examples. For examples such as artemisinin, rubber, stevioside, and steroids, the biotechnical production and the respective areas of application in technology and medicine are presented.