The key to developing synthetic membranes for large-scale, energy-efficient liquid separations is materials research. In the domains of materials science and chemistry, carbon quantum dot (CQD) is a rising star. Whereas the efficiency of membrane separation applications can be proven only when commercial products are available, CQD no longer requires any added layer of its importance in terms of fundamental chemistry. Albeit still in its infancy, this strictly zero-dimensional material has already revealed a cornucopia of potential membrane separation applications, serving as a fertile ground for this technology. More broadly, a new paradigm of properties on demand has emerged as a consequence of CQDs’ exceptionally high tunability and biocompatibility, allowing for the tailored design of liquid-separation membranes in table-top investigations, all of which are systematically discussed here. In this review, we highlight the key selling points of CQDs in the property-performance relationships of CQD-incorporated membranes, delivering insights into these materials’ potential that may eventually lead to their use in membrane separation. These cutting-edge materials pave the path for a brand-new generation of membrane processes that surpass the boundaries of existing approaches and materials.