Marine organisms represent a valuable source of nutraceuticals and functional compounds. The biodiversity of the marine environment and the associated chemical diversity constitute a practically unlimited resource of novel active substances for the development of bioactive products. Recently, a great deal of interest has been expressed in marine-derived bioactive peptides because of their numerous beneficial health effects. Moreover, several studies have reported that marine bioactive peptides can be used as antihypertensive, antioxidative, anticoagulant, and antimicrobial components in functional foods or nutraceuticals and pharmaceuticals due to their therapeutic potential in the treatment or prevention of disease. In this chapter, we provide an overview of bioactive peptides derived from marine organisms as well as information about their biological properties and mechanisms of action with potential applications in different areas.