The teenager's alleged assault and hanging is the fourth case to be reported in Uttar Pradesh state in less than a month.
A day earlier, the body of a 44-year-old woman was discovered hanging from a tree in a remote village in the Bahraich area. Police suspect she may have been attacked by locals angered she was selling liquor in the area. A post-mortem exam to determine whether she had been sexually assaulted was inconclusive, although her family believes she was gang-raped.
Sexual violence against women in India has sparked public outrage.
Protesters took to the streets of Uttar Pradesh after two girls, ages 14 and 16, were gang-raped and hanged in the Budaun district in late May.
Uttar Pradesh is a large Indian state that is home to more than 200 million people, many of whom are poor and low-caste.