Diwali (English: ), also known as Deepawali or the Festival of Lights, is one of the most important festivals in Indian religions. It symbolises the spiritual "victory of light over darkness, good over evil, and knowledge over ignorance". The festival is widely associated with conflagrations between good and evil entities.

Diwali is a post-harvest festival celebrating the bounty following the arrival of the monsoon in the subcontinent. It is celebrated during the Hindu lunisolar months of Ashvin (according to the amanta tradition) and Kartika (between mid-October and mid-November). In Hinduism it generally lasts five or six days.

Diwali is connected to various religious mythical events or personalities. The day Rama returned to his kingdom in Ayodhya with his wife Sita and his brother Lakshmana after defeating the demon Ravana. Birth of Lakshmi (goddess of prosperity). Ganesha (god of wisdom and the remover of obstacles). Other regional traditions connects the holiday to Sita and Rama, Vishnu, Krishna, Durga, Shiva, Kali, Hanuman, Kubera, Yama, Yami, Dhanvantari, or Vishvakarman.

During the festival, Hindus, Jains and Sikhs illuminate their homes, temples and workspaces with diyas (oil lamps), candles and lanterns Hindus, in particular, have a ritual oil bath at dawn on each day of the festival. Diwali is also marked with fireworks and the decoration of floors with rangoli designs, and other parts of the house with jhalars. Food is a major focus with families partaking in feasts and sharing mithai.

The festival is an annual homecoming and bonding period not only for families, but also for communities and associations, particularly those in urban areas, which will organise activities, events and gatherings. Many towns organise community parades and fairs with parades or music and dance performances in parks. Some Hindus, Jains and Sikhs will send Diwali greeting cards to family near and far during the festive season, occasionally with boxes of Indian confectionery. Another aspect of the festival is remembering the ancestors.

Originally a Hindu festival, Diwali is now also celebrated by other faiths. The Jains observe their own Diwali which marks the final liberation of Mahavira, the Sikhs celebrate Bandi Chhor Divas to mark the release of Guru Hargobind from a Mughal prison. Newar Buddhists, unlike other Buddhists, celebrate Diwali by worshipping Lakshmi, while the Hindus of Eastern India and Bangladesh generally celebrate Diwali by worshipping the goddess Kali.

Diwali is also a major cultural event for the Hindu, Sikh, and Jain diaspora. The main day of the festival of Diwali (the day of Lakshmi Puja) is an official holiday in Fiji, Guyana, India, Malaysia, Mauritius, Myanmar, Nepal, Pakistan, Singapore, Sri Lanka, Suriname, and Trinidad and Tobago.