Many research efforts have been directed toward producing carbon nanotubes (CNT)/polymer nanocomposites for functional and structural applications1-5. However, even after a decade of research, the full potential of employing CNTs as reinforcements is severely limited because of the dif“culties associated with dispersion of CNTs during processing and poor interfacial interaction between the CNTs and the polymer matrix. The nature of the dispersion problem for CNTs is different from other conventional “llers, such as spherical particles and carbon “bers, because CNTs have a diameter on a nanometer scale with a high aspect ratio (>1000) and an extremely large surface area. In addition, commercial CNTs are supplied in the form of heavily entangled bundles, aggravating the dif-“culties of dispersion in a polymer. In this chapter, fundamental issues regarding CNT dispersion, including the nature of dispersion problems, techniques and mechanisms for dispersion, and dispersion behavior of CNTs affected by solvents and surfactants are discussed.