In Hinduism, there are sixteen samskaras i.e., the rites of passage of human being from birth to death. Upanayana is one of those, a journey for a Hindu Brahmin boy to enter the life of a student or Brahmacharin. According to the Hindu belief, a Brahmin boy is born twice, once physically and secondly, spiritually, thus, called Dvija i.e., twice born. This second life starts at the early stage of life of a Brahmin boy when he is offered a sacred thread through the Upanayana ceremony. This sacred thread i.e., yajnopavita is given by an acharya or teacher, to be worn by the boy, which is believed to protect him from negative energy. The ritual includes shaving of the head following a sacramental bath, and wearing of a dress like a celibate the boy is taken to his acharya. The acharya gives him with a deerskin as an upper garment, a mekhala (girdle), a danda (staff), and the sacred thread (yajnopavita). The acharya chants the Gayatri mantra in low voice in the ear of the boy, which is to be recited by the boy thrice a day. The ritual concludes with setting on the sacrificial fire and the boy begs for alms, which symbolizes his dependence on others during his brahmacharin life. However, the age of Upanayana differs from eight years to eleven years. If not done during this age, it may be performed before the wedding of the groom. The sacred thread ceremony was initially prevalent to three upper varnas or classes of the Hindus but nowadays, it is limited to only Brahmins. In ancient times, girls who wanted to be student, underwent this ritual to wear yajnopavita and they were known as Brahmavadini. This article tries to note an authentic information of the ritual, its symbolism, and the social and religious significance of the Upanayana.