Arti (Hindi: आरती, romanized: Āratī) or Aarati (Sanskrit: आरात्रिक, romanized: Ārātrika) is a Hindu ritual employed in worship, part of a puja, in which light from a flame (fuelled by camphor, ghee, or oil) is ritually waved to venerate deities. Arti also refers to the hymns sung in praise of the deity, when the light is being offered. Sikhs have Arti kirtan which involves only devotional singing; the Nihang order of Sikhs also use light for arti.

Aarti is thought to have descended from Vedic fire rituals or yajna. Aarati is derived from the Sanskrit word आरात्रिक (ārātrika) which means something that removes rātrī, "darkness". A Marathi language reference says it is also known as Mahānīrāñjanā (Sanskrit: महानीराञ्जना). According to Steven Rosen, arti means "before night" or symbolic end of the night to the worshipper's "material sojourn – he or she is now situated in the light of God's devotion."

Aarti ranges from simple acts of worship to extravagant rituals, but almost always includes a jyoti (flame or light). It is performed up to eight times daily, depending on the specific Hindu tradition and temple. It is performed as part of most Hindu liturgies and occasions and typically involves circling a diya (lamp) clockwise before a murti or icon of a deity, accompanied by hymns. After waving the lamp before the deity, it is brought to the devotee, who then briefly places both their palms above the sanctified flame to receive its warmth. The devotee then raises their hands in supination, bringing both palms toward to their forehead in a gesture of self-purification and connection with the Divine.

The diya (lamp) used for aarti is most often made of brass or other materials and holds a cotton wick soaked in camphor, ghee, or oil. The aarti plate may contain other offerings like flowers, incense, and akshata (rice).

The purpose of aarti is to wave light before the deity in a spirit of humility and gratitude, wherein the faithful become immersed in a God's divine form. All accoutrements used for aarti symbolize the five elements:

Aarti may also be performed at shrines within a business or home.

Arti is an expression of many aspects including love, benevolence, gratitude, prayers, or desires depending on the object for which it is performed. For example, it can be a form of respect when performed for elders, prayers when performed to deities, or hope when performed for homes or vehicles. Emotions and prayers are often silent while doing arti, but this is determined by the person carrying out the ritual or the holiday involved. It's also believed that goodwill and luck can be taken through symbolic hand movements over the flame.

Apart from worldly activities, arti also represents one's self - thus, arti signifies that one is peripheral to godhead or divinity. This would keep one's ego down and help one remain humble in spite of high social and economic rank. A third commonly held understanding of the ritual is that arti serves as a reminder to stay vigilant so that the forces of material pleasures and desires cannot overcome the individual. Just as the lighted wick provides light and chases away darkness, the vigilance of an individual can keep away the influence of the material world.