Hexagonal boron nitride (h-BN), a layered material isostructural to graphite, has similar exotic properties like graphite. With single atom thick and alternating boron and nitrogen atoms in its atomic structure, h-BN is an insulator with band gap ~ 5.9 eV. As monolayer h-BN or boron nitride nanosheet (BNNS) has been studied for over a decade, a brief overview about the structure and stability is provided. In addition, this chapter provides insight into the different forms of h-BN focusing mainly on the synthesis of single layer h-BN or BNNS via different techniques such as mechanical exfoliation, solvent exfoliation, and chemical vapor deposition. Along with BNNS, h-BN nanoribbon synthesis is also presented as it follows a similar approach to BNNS. As h-BN is the insulating isostructure to graphene, use of h-BN in some of the major applications such as coatings, dielectric, and some device applications are also discussed.