The ancient Indian epic associated with Diwali’s origin story in northern India is the Ramayana.
In the best-known northern Indian tradition, Diwali celebrates Rama’s return to Ayodhya after 14 years of exile and his victory over Ravana. Rama returns with Sita and Lakshmana, and the people of Ayodhya are said to have illuminated the city with rows of oil lamps. This story gives the festival its powerful imagery of light triumphing over darkness and righteousness overcoming evil.
The Ramayana is an ancient Sanskrit epic traditionally attributed to the sage Valmiki. Its stories have spread through many regional languages, oral traditions, performances, devotional texts, and retellings across South and Southeast Asia.
The Ramayana is the expected answer for northern India, but Diwali does not have one universal origin story. Other regional traditions connect it with Krishna’s defeat of Narakasura, Lakshmi, Kali, or Govardhan Puja. Those variations do not displace the Ramayana as the canonical answer to this specifically northern Indian question.