For Jains, what event does Diwali commemorate?

For Jains, Diwali commemorates Mahavira’s nirvana.

Mahavira was the 24th and final Tirthankara of the current Jain time cycle. Jain tradition holds that he attained nirvana at Pawapuri in present-day Bihar, bringing his soul’s cycle of birth and death to an end. This is why Jain Diwali is often called Mahavira Nirvana Divas.

The answer is sometimes loosely described as Mahavira’s death, but nirvana is more precise: it refers to final spiritual liberation, not merely the end of bodily life. His birth is observed at Mahavir Janma Kalyanak, while enlightenment—or kevala jnana—belongs to an earlier stage of his life. Jain communities mark Diwali with temple visits, prayers, lamps, and offerings such as Nirvan Ladoo. The festival also begins the Jain New Year on the following day.