In recent years, quantum dot-sensitized solar cells (QDSSCs) have emerged as attractive candidates for constructing efficient third-generation photoelectrochemical solar cells. Despite a starting point of relatively low performing solar cells, we have been witnessing a boost in scientific research conducted both from the material and the physical points of view, leading to a huge leap in our understanding of the operational mechanisms of QDSSCs followed by a significant improvement of their conversion efficiencies to about 7%. In this feature article, we give an overview of the four main materials and interfaces constructing the QDSSC: (1) sensitizer materials, (2) TiO2/QDs/electrolyte interface, (3) redox electrolyte, and (4) counter electrode. We focus on the scientific challenges associated with each one of the materials/interfaces while highlighting the recent advances achieved in overcoming those obstacles. Finally, we discuss possible future directions for this field of research with an aim toward highly efficient QD-sensitized solar cells.