Puja (Sanskrit: पूजा, romanized: pūjā) is a worship ritual performed by Hindus, Buddhists and Jains to offer devotional homage and prayer to one or more deities, to host and honor a guest, or to spiritually celebrate an event. It may honor or celebrate the presence of special guests, or their memories after they die. The word pūjā is Sanskrit, and means reverence, honor, homage, adoration, and worship. Puja, the loving offering of light, flowers, and water or food to the divine, is the essential ritual of Hinduism. For the worshipper, the divine is visible in the image, and the divinity sees the worshipper. The interaction between human and deity, between human and guru, is called darshan, seeing.

In Hindu practice, puja is done on a variety of occasions, frequencies, and settings. It may include a daily puja done in the home, or occasional temple ceremonies and annual festivals. In other cases, puja is held to mark a few lifetime events such as the birth of a baby or a wedding, or to begin a new venture. The two main areas where puja is performed are in the home and at temples to mark certain stages of life, events or some festivals such as Durga Puja and Lakshmi Puja. Puja is not mandatory in Hinduism. It may be a routine daily affair for some Hindus, a periodic ritual for some, and rare for other Hindus. In some temples, various pujas may be performed daily at various times of the day; in other temples, they may be occasional.

Puja varies according to the sect, region, occasion, deity honored, and steps followed. In formal Nigama ceremonies, a fire may be lit in honor of the god Agni, without an idol or image present. In contrast, in Agama ceremonies, an idol or icon or image of a deity is present. In both ceremonies, a lamp (Diya) or incense stick may be lit while a prayer is chanted or a hymn is sung. Puja is typically performed by a Hindu worshiper alone, though sometimes in the presence of a priest who is well-versed in complex rituals and hymns. In temples and priest-assisted events puja, food, fruits, and sweets may be included as sacrificial offerings to the ceremony or deity, which, after the prayers, becomes prasad – food shared by all gathered.

Both Nigama and Agama puja are practiced in Hinduism in India. In Hinduism of Bali Indonesia, Agama puja is most prevalent both inside homes and in temples. Puja is sometimes called Sembahyang in Indonesia.