Hydrogen is a promising candidate as a clean and green energy source due to its eco-friendly and renewable characteristics. The development of efficient and low-cost electrocatalysts for solar-driven hydrogen generation has great promise to meet the future energy requirements. Quantum dots (QDs) as photocatalysts are attractive for use to boost the properties of metal oxide semiconductors for obtaining efficient photoelectrodes in photoelectrochemical (PEC) devices to produce hydrogen. In this chapter, we first briefly introduce the working principle of QDs in PEC systems and then discuss the relationship between structure and optical properties of the QDs. We further discuss the synthetic techniques of QDs and introduce the methods of sensitization of QDs/semiconductor photoelectrodes. In the end, we conclude with a detailed account of the latest research progress in structure, materials, and performance of PEC systems for hydrogen generation based on various types of QDs and further perspective on the remaining key issues and opportunities in the field.