Pectin is a structurally complex acidic polysaccharide ubiquitously distributed in terrestrial plant cell walls, particularly in the middle lamella and primary walls of meristematic and parenchymatous tissues. Its molecular architecture varies with species, tissue type, and developmental stage, yet the biosynthetic mechanisms governing this diversity remain incompletely understood. Industrially, pectin has long been used as a gelling agent, thickener, and stabilizer in foods, and it represents a major source of soluble dietary fiber with expanding applications in cosmetic and pharmaceutical sectors. Beyond its technological functionality, accumulating evidence indicates that pectin exerts health-promoting effects through physicochemical interactions, modulation of gut microbiota, and direct actions on the intestinal epithelium. Future research priorities include elucidating structure–function relationships, protein–pectin interactions in the intestine, and advanced analytical methodologies to characterize domain architectures such as homogalacturonan and rhamnogalacturonan-I. These efforts are expected to enable structure-defined pectin design and foster novel industrial applications.