The genus Bidens belongs to the family Asteraceae, comprising numerous species distributed globally. It is recognized for its rich diversity of secondary metabolites, with terpenoids being particularly noteworthy, including monoterpenes, sesquiterpenes, and diterpenes, each contributing distinct aromatic and biological properties. Terpenoids regulate essential processes in plant development and growth, acting as signaling molecules and modulating responses to abiotic and biotic stresses. This chapter explores the diverse roles and biosynthesis of terpenoids in the genus Bidens. Terpenoids in Bidens species, including Bidens pilosa, Biden tripartita, and Bidens bipinnata, play crucial roles in plant biology and human health. The chapter covers their classification, biosynthesis pathways (MVA and MEP), evolutionary insights into terpene synthase genes, and functional roles in plant development and stress responses. Applications in medicine, industry (flavors, fragrances), and future perspectives in biotechnology are also discussed.