The discovery of new drugs, poor patient compliance, limitations of the conventional dosage forms, and switching to more suitable routes of administration have led to the development of new dosage forms, which in turn demands innovation/discovery of pharmaceutical excipients. In addition to number of excipients, the addition of polymer(s) in drug formulation(s) is unavoidable, as this plays a vital role in the stability, solubility, release, and bioavailability of the drug. The selection of an excipient with ideal properties such as non-toxicity, stability, excess availability, biodegradability, biocompatibility, ease of processing, contaminant-free, and non-allergic response are the major concerns. These issues can be addressed by using cellulose, its derivatives, and different forms as drug delivery systems. To this end, nanocellulose (NC) has received great interest due to its outstanding mechanical, rheological, chemical, and optical properties. It serves as an eco-friendly and sustainable material with vast pharmaceutical applications and is obtained from numerous natural sources of cellulose. NC is hydrophilic in nature; however, the alteration of its surface properties may enhance its applications to meet the challenges of the future. The cellulose produced by microbes, also known as bacterial/microbial cellulose, is a biomaterial with fascinating properties including extremely high purity, high porosity, ultrafine fiber network, high water holding capacity, great tensile strength, and permeability to diffusion of liquids, gases, and small molecules. In the field of drug delivery, cellulose plays a pivotal role in dosage formulations in the form of filler, stabilizer, thickening agent, coating agent, in the preparation of transdermal patches, controlled drug delivery, protein delivery, and macromolecular pro-drug delivery. The current chapter gives an overview of the applications of nanocellulose in drug delivery based on the available literature. An explorative look to NFC applications in the pharmaceutical field and various approaches adopted in the field of drug delivery are also discussed. The approaches made for the safe, effective, and convenient delivery of drugs into body are discussed in detail. Based on current literature, it is suggested that further experimental work is required for the exploration of NFC applications in the stimuli-responsive delivery of drugs.