<p>Guided by a sustainable and scalable energy storage strategy, with the continuous innovation of cathode materials for sodium-ion batteries (SIBs), layered oxide cathode materials have sparked intense interest in the scientific community due to their unique structures and excellent properties. However, there are also some problems, such as poor structural stability, slow sodium ion diffusion kinetics, severe lattice distortion caused by the Jahn–Teller effect, and poor reversibility of oxygen redox reactions at high voltages. In view of this, the high-entropy strategy offers a feasible solution for optimizing the electrochemical performance of layered oxide cathode materials. This paper reviews the classification of layered oxide materials and the issues they face, elaborates on the modification methods for improving the electrochemical performance of layered oxides, analyzes the synthesis methods and grain growth mechanisms of high-entropy oxides, comprehensively summarizes the current research status of high-entropy oxide materials used as cathodes for SIBs. At the same time, it deeply explores the advantages of the high-entropy strategy in the modification of layered oxide cathode materials, and prospects the opportunities and challenges for the future development of layered high-entropy oxide cathode materials.</p>