This chapter synthesizes recent advances in marine shellfish protein research, focusing particularly on umami peptides derived from these proteins. First, it highlights the fundamental role of umami taste perception mediated by its specific receptors. Next, the chapter systematically reviews the classification and signaling mechanisms of umami receptors. Subsequently, it explores umami peptide production methods, including enzymatic hydrolysis, chemical synthesis, enzymatic approaches, biotechnological production, and microbial fermentation, and evaluates analytical characterization techniques, such as sensory evaluation by trained panels and electronic tongue analysis. Finally, it examines the structure–activity relationships of umami peptides, analyzing key structural determinants, including molecular weight, amino acid composition, and sequence configuration. The chapter concludes with an exploration of AI-driven approaches for accelerating umami peptide discovery and development.