Sikhs do not celebrate Diwali for the same reason as other Indian religions, although the story of Diwali is celebrated for its spiritual significance.
Sikhs celebrate Bandi Chhor Divas (often translated as Prisoner Release Day) on Diwali. This is the occasion of the return of the sixth Guru, Guru Hargobind Sahib Ji, who was freed from imprisonment in 1619. He was imprisoned because he introduced the process of militarization to Sikhism to defend against oppression and to protect humanity from the Mughals, who were in reign at the time. He was a dedicated enemy of the Mughal rule and he refused to convert himself and the other Sikhs to Islam due to which he was finally captured by Jahangir, the Mughal Emperor of the time. When Guru Hargobind Sahib Ji was granted release from prison he refused to leave until 52 Hindu political prisoners were also released by Emperor Jahangir. Jahangir agreed to release as many men who could hold onto Guru Ji’s robe. For this reason, Guru Ji had a special robe made with 52 tassels, allowing all the 52 political prisoners with Him. Guru Ji arrived home to His followers around the time of Diwali, which has long been a national holiday in India.
Sikhs go to the Gurdwara and remember Guru Ji through prayer and meditation. Sikhs also light divas and set off fireworks, which is the traditional manner of celebration for the Festival of Lights. Sikhs light up the Golden Temple in Amritsar, and wear new or nice clothes while exchanging sweets as well.