Nanocomposites are the innovative form of materials used at the nanoscale (1–100 nm in size). Parent materials are insufficient to satisfy the desired requirement to fulfill all the needs, hence to enhance various performances of composites, a suitable nanofiller (nanoparticle) can be used. The present study focuses on nanocomposite properties, types, and characteristic features. Nanocomposites that take advantage of fibers and nanofillers synergistically contribute to improved properties and environmental conditions by making them suitable for a wide range of applications (aerospace, automobile industries, electronics, biomedical, etc.). Nanocomposites are now being used in almost every field and find a wide spectrum of applications, including waste water treatment, corrosion protection, and so forth. In the present study, the effect of excessive use of nanoparticles (nanotoxicity) has also been addressed.