We report a facile approach to using laponite (LAP) nanodisks as a platform for efficient delivery of doxorubicin (DOX) to cancer cells. In this study, DOX was encapsulated into the interlayer space of LAP through an ionic exchange process with an exceptionally high loading efficiency of 98.3 ± 0.77%. The successful DOX loading was extensively characterized via different methods. In vitro drug release study shows that the release of DOX from LAP/DOX nanodisks is pH-dependent, and DOX is released at a quicker rate at acidic pH condition (pH = 5.4) than at physiological pH condition. Importantly, cell viability assay results reveal that LAP/DOX nanodisks display a much higher therapeutic efficacy in inhibiting the growth of a model cancer cell line (human epithelial carcinoma cells, KB cells) than free DOX drug at the same DOX concentration. The enhanced antitumor efficacy is primarily due to the much more cellular uptake of the LAP/DOX nanodisks than that of free DOX, which has been confirmed by confocal laser scanning microscope and flow cytometry analysis. The high DOX payload and enhanced antitumor efficacy render LAP nanodisks as a robust carrier system for different biomedical applications.