The demand for energy is increasing tremendously with modernization of the technology and requires new sources of renewable energy. The triboelectric nanogenerators (TENG) are capable of harvesting ambient energy and converting it into electricity with the process of triboelectrification and electrostatic-induction. TENG can convert mechanical energy available in the form of vibrations, rotation, wind and human motions etc., into electrical energy there by developing a great scope for scavenging large scale energy. In this review paper, we have discussed various modes of operation of TENG along with the various factors contributing towards its efficiency and applications in wearable electronics.