|Observed by||Religiously by Bengalis Hindus|
|Date||Decided by the lunar calendar|
|Observances||Prayers, Religious rituals (see puja, prashad)|
Kali Puja or Shyama Puja is a festival dedicated to the Hindu goddess Kali, celebrated on the new day of the Hindu month Ashwin in Bengal. It coincides with the pan-Indian Lakshmi Puja day of Diwali. While rest of India worships goddess Lakshmi, Bengalis, Oriyas and Assamese adore Kali.
The festival of Kali Puja is not an ancient one. Kali Puja was practically unknown before the 18th century, however a late 17th century devotional text Kalika mangalkavya –by Balram mentions an annual festival dedicated to Kali It was introduced in Bengal during the 18th century, by King (Raja) Krishnachandra of Navadvipa. Kali Puja gained popularity in the 19th century, with Krishanachandra’s grandson Ishvarchandra and the Bengali elite; wealthy landowners began patronizing the festival on a grand scale. Along with Durga Puja, now - Kali Puja is the biggest goddess festival in Bengal.
On Kali puja (like Durga Puja) worshipers honor goddess Kali in their homes in the form of clay idols and in pandals (temporary shrines or open pavilions). She is worshipped at night with Tantric rites and mantras. She is prescribed offerings of red hibiscus flowers, animal blood in a skull, sweets, rice and lentils, fish and meat. It is prescribed that a worshipper should mediate throughout the night until dawn. Homes may also practice rites in the Brahmanical (mainstream Hindu-style, non-Tantric) tradition with ritual dressing of Kali in her form as Adya Shakti Kali. Animals are ritually sacrificed on Kali Puja day and offered to the goddess. A celebration of Kali Puja in Kolkata is also held in a large cremation ground. where she is believed to dwell.
The pandals also house images of god Shiva - the consort of Kali, Ramakrishna and Bamakhepa- two famous Bengali Kali devotees along with scenes from mythology of Kali and her various forms along with Mahavidyas, sometimes considered as the "ten Kalis". The Mahavidyas is a group of ten Tantric goddesses headed by Kali. People visit these pandals throughout the night. Kali Puja is also the time for magic shows and theatre, fireworks.Recent custom involves drinking wine on Kali Puja.
In the Kalighat temple in Kolkata, Kali is worshipped as Lakshmi on this day, reflecting an essence of Vaishnava Haldars on Kali worship. The temple is visited by thousands of devotees on this day - who also offer animal sacrifice to the goddess. Another famous temple dedicated to Kali is Dakshineswar Kali Temple in Kolkata. The famous Kali devotee Ramakrishna was a priest at this temple and the celebrations have changed little from his times.
-  Encountering Kālī: in the margins, at the center, in the West By Rachel Fell McDermott, Jeffrey John Kripal
- Offering flowers, feeding skulls: popular goddess worship in West Bengal By June McDaniel 
- Kali: the black goddess of Dakshineswar By Elizabeth U. Harding 
- Mother of my heart, daughter of my dreams By Rachel Fell McDermott 
- Tantric visions of the divine feminine: the ten mahāvidyās By David R. Kinsley 
- The camphor flame: popular Hinduism and society in India By Christopher John Fuller uk:Калі-Пуджа