Nanomaterials have made huge contributions to our lives over the past few decades. Increasing commercial applications of this technology have led to intensive research and development. The term nanofiller refers to fillers with particle sizes between one and a hundred nanometers. Carbon blacks, synthetic silicas, and precipitated calcium carbonate are well-established fillers but do not qualify as nanoparticles because they agglomerate into bigger, more stable particles after a short time. Among the new materials, quantum dots, nanowires, nanotubes, layered silicates, polyhedral oligomeric silsesquioxanes, dendrimers, metal oxides, and graphene oxides have just been discovered. Various nanofillers have recently entered the commercial market, including nanoclays (montmorillonite, smectite), needle-shaped nanowhiskers, and nanoparticles. For instance, the exfoliation of nanoclays (separation of the material into individual layers) results in the formation of primary reinforcing particles with extraordinarily high aspect ratios (higher than 200). The surface modification process known as intercalation by chemicals with ammonium or phosphonium functional groups improves exfoliation. As a result, the surface becomes organophilic rather than hydrophilic. These fillers possess good mechanical properties at low loadings, scratch resistance, superior barrier properties, enhanced fire resistance properties, and improved heat distortion properties when compared to neat polymers. Automotive and industrial components, packing films, and rigid containers are the current major applications. This chapter explores these materials, emphasizing their physical and chemical characteristics, several kinds of nanofillers, a variety of nanocomposites, and conclusions made. In addition, the recent advantages, current state of art, and the development of nanofillers in different fields will be discussed.