One-dimensional carbon nanotubes (CNTs) have outstanding mechanical properties, making them a good candidate for reinforcement application in polymer and fiber-reinforced polymer composites. Superior properties of the CNTs are exploited regularly by reinforcing these nanotubes in a polymer matrix. However, strong Van der Waals interaction energy of tube-tube contact, high electrostatic interaction between the tubes, small tube size, and large surface area of the tubes render CNT dispersion a problematic task. Therefore, to improve its dispersion and alignment in the composite, researchers have developed innovative techniques to strengthen the properties of the composite. For achieving optimum and reproducible mechanical properties in a composite, fine dispersion of CNTs, their alignment, and strong interfacial adhesion with polymer is a demand to be guaranteed. In this chapter, the principles and techniques for uniform dispersion and alignment of CNTs in the polymer and fiber-reinforced polymer composite are discussed.