As one of the most promising cathode materials for sodium-ion batteries, sodium-ion layered oxide has the advantages of high capacity and low cost, which makes sodium-ion batteries have great application prospects in large-scale static energy storage. However, their commercial development has been limited due to poor electrochemical cycle stability and air stability. Compared with traditional polycrystalline layered oxides, single-crystalline layered oxides are characterized by high mechanical strength, low specific surface, and high taping density, and thus can effectively improve the cycling stability of layered oxides and enhance their comprehensive performance. The basic structure types of layered oxides of sodium-ion batteries are introduced in the paper.The synthesis methods of single-crystal layered oxides of sodium-ion batteries that have been reported so far are also reviewed and the advantages and disadvantages of various synthesis methods are analyzed. Besides, the improvement of single-crystal morphology on comprehensive performance is described and the research status of single-crystal layered oxides in sodium-ion batteries is presented with an outlook of the future development of single-crystal layered oxides for sodium-ion batteries.