SummaryOceans cover over 70% of the Earth's surface and provide home to structurally diverse marine organisms. These creatures contribute to more than half of the biodiversity of the world and produce several bioactive molecules, including peptides. In the past years, scientific research has been focused on the compositions, sequences and structural features of marine‐derived peptides. Based on their amino acid sequences, they have demonstrated a wide range of biological functions, including antithrombotic, antihypertensive, anticancer, antioxidant, antimicrobial, antiageing, anti‐inflammatory, immunomodulatory and other multifunctional activities that are based on their structure, hydrophobicity, binding affinity, charge and other factors. This review focuses on novel techniques used to produce marine peptides and explores the structure–function relationships of these peptides derived from representative phyla, namely Cnidaria, Annelida, Mollusca, Arthropoda, Chordata, Echinodermata and Porifera. Furthermore, notable considerations regarding the structure–function basis of marine peptide applications are discussed.