Sustainable hydrogen production via water electrolysis is pivotal to addressing global energy and environmental challenges. Among emerging materials, quantum dots (QDs) have garnered significant attention for the hydrogen evolution reaction (HER) due to their zero-dimensional nanostructure, high specific surface area, tunable electronic characteristics, and abundant active sites. This review provides a comprehensive overview of recent advancements in QD-based catalysts for electrocatalytic HER, focusing on the fundamental mechanisms that drive their enhanced performance. Key enhancement strategies—such as substrate dispersion, surface functionalization, defect engineering, and heteroatom doping—are critically discussed. Furthermore, the review explores the potential of QD-based catalysts for large-scale and industrial applications. By synthesizing current progress and challenges, this review offers critical insights into the rational design of next-generation HER catalysts to advance sustainable hydrogen energy.