Abstract: Supercapacitors are a new type of energy storage device that has seen great improvement in recent years. Due to their hollow cores, high electrical conductivity and high specific surface area, carbon nanotubes (CNTs) are regarded as one of the most promising electrode materials for supercapacitors. In this paper, progress on the application of CNTs in supercapacitors is reviewed. The properties of CNTs, activated CNTs, CNT/metal oxide composites and CNT/conductive polymer composites as electrode materials are discussed. The specific capacitance of supercapacitors based on CNTs is not very high because of their low specific surface area. Chemical activation of the CNTs can greatly enhance their specific surface area and hence enhance their specific capacitance. Composites of CNTs and pseudocapacitance materials (metal oxides or conducting polymers), which possess the desirable properties of both components, are promising electrode materials for supercapacitors because of their low cost and good properties.