Terpenoids represent a structurally diverse class of plant-derived bioactive compounds with a wide range of physiological functions. This chapter outlines the classification and dietary sources of terpenoids and highlights their antioxidant, anti-inflammatory, and metabolic regulatory properties. Particular emphasis is placed on their interaction with key molecular targets, including nuclear receptors and membrane-bound signaling pathways such as GPCRs. Recent findings on the activation of TGR5 by dietary terpenoids—including nomilin, obacunone, and maslinic acid—are discussed in the context of muscle hypertrophy, energy metabolism, and glucose homeostasis. The multifaceted actions and low toxicity of terpenoids support their potential as functional food factors for the prevention and management of lifestyle-related diseases. Future perspectives on their bioavailability, formulation strategies, and clinical application are also addressed.