In recent years, several studies have been performed using nanocellulose as a component in polymeric nanocomposites. The interest in studying cellulose-based nanocomposite is due to the abundance, renewable nature, and outstanding mechanical properties of this nanoparticle. However, obtaining nanocomposites based on nanocellulose, with optimal properties, requires good nanoparticle dispersion in the polymeric matrix. The chemical compatibility between nanofiller and polymer plays a major role in both the dispersion of particles in the matrix and the adhesion between these phases. The aim of this review is to present the fundamental concepts about nanocellulose, such as its structural aspects, production methods and current trends in classification, and the main aspects about cellulose-based nanocomposites, including the progress that has been reached in relation to their compatibilization, production, final properties and potential applications.