Chitosan is a naturally derived biopolymer obtained by the deacetylation process of chitin. It is a non-toxic, biocompatible, and biodegradable polymer with randomly arranged D-glucosamine and N-acetyl-D-glucosamine units. The free amino groups in the polymer chain can get protonated in acidic pH rendering it cationic and allowing it to interact with other biological macromolecules. The tunable porosity, gelation ability, and structural resemblance of chitosan with glycosaminoglycans (GAGs) make it an ideal candidate for pharmaceutical applications. Chitosan’s versatility is further demonstrated by its derivatization and fabrication into different forms such as scaffolds, sponges, beads, nanoparticles, microparticles, hydrogel, cryogel, films, and membranes, expanding its use in the pharmaceutical sector. It also has been used as an excipient in drug formulations along with its multitude of applications in drug delivery, gene delivery, wound healing, and tissue engineering. This chapter focuses on the pharmaceutical aspects and applications of the biopolymer chitosan in the pharmaceutical field.