Mohini (Sanskrit: मोहिनी, Mohinī) is the Hindu goddess of enchantment. She is the only female avatar of the Hindu god Vishnu. She is portrayed as a femme fatale, an enchantress, who maddens lovers and demons, sometimes leading them to their doom. Mohini is introduced into Hinduism in the narrative epic of the Mahabharata. Here, she appears as a form of Vishnu following the Churning of the Ocean, a mesmerising beauty who distributes the amrita (the elixir of immortality) to the weakened devas (gods) and depriving it to the dominant asuras (demons), allowing the former to defeat the latter with their newfound immortality.

Many different legends tell of her various exploits, including her famed encounter with the god Shiva. These tales relate, among other things, the birth of the god Shasta and the destruction of Bhasmasura, the ash-demon. Mohini's main modus operandi is to trick or beguile those she encounters. She is worshipped throughout Indian culture, but mainly in Western India, where temples are devoted to her in the form of Mhalsa— where she is worshipped as Mahalasa Narayani.

The name Mohini comes from the verb root moha, meaning "to delude, enchant, perplex, or illusion," and literally means "delusion personified." In the Baiga culture of Central India, the word mohini means "erotic magic or spell." The name also has an implied connotation of "the essence of female beauty and allurement."

The earliest reference to a Mohini-type goddess appears in the Samudra Manthana episode of the 5th century BCE Hindu epic Mahabharata. The Amrita, or nectar of immortality, is produced by the churning of the Ocean of Milk. The Devas and the Asuras fight over its possession. The Asuras contrive to keep the Amrita for themselves, angering the Devas. Vishnu, wise to their plan, assumes the form of an "enchanting damsel". She uses her allure to trick the Asuras into giving her the Amrita, and then distributes it amongst the Devas. Rahu, an Asura, disguises himself as a god and tries to drink some Amrita himself. Surya (the sun-god) and Chandra (the moon-god) quickly inform Vishnu, and he uses the Sudarshana Chakra (the divine discus) to decapitate Rahu, leaving the head immortal. The other major Hindu epic, Ramayana (4th century BCE), narrates the Mohini story briefly in the Bala Kanda chapter. This same tale is also recounted in the Vishnu Purana four centuries later.

In the original text, Mohini is referred to as simply an enchanting, female form of Vishnu. In later versions, Mohini is described as the maya (illusion) of Vishnu. Later still, the name of the avatar becomes Mohini from the original phrase describing his deliberate false appearance (mayam ashito mohinim). Once the Mohini legend became popular, it was retold, revised, and expanded in several texts. The tales of Mohini-Vishnu also increased among devotional circles in various regions. The same expanded Mahabharata version of the story is also recounted in the Bhagavata Purana in the 10th century CE. Here, Mohini becomes a formal avatar of Vishnu.

This legend is also retold in the Padma Purana. and Brahmanda Purana. In the Brahmanda Purana, however, Vishnu-Mohini simply, after meditation upon the Great Goddess Maheshvari, acquires her form to trick the thieving asuras.

Mohini also has an active history in the destruction of demons throughout Hindu texts. In the Vishnu Purana, Mohini defeats Bhasmasura, the "ash-demon". Bhasmasura invokes the god Shiva by performing severe penances. Shiva, pleased with Bhasmasura, grants him the power to turn anyone into ashes by touching their head. The demon decides to try the power on Shiva himself. Shiva requests Vishnu for help and Vishnu transforms into Mohini and charms Bhasmasura. Bhasmasura is so taken by Mohini that he asks her to marry him. Mohini agrees, but only on the condition that Bhasmasura follows her move for move in a dance. In the course of the dance, she places her hand on her head. Bhasmasura mimics the action, and in turn, reduces himself to ashes. The legend of Bhasmasura is retold in the Buddhist text Satara Dewala Devi Puvata, with a slight variation. In this tale, Vishnu assumes his female form (the name "Mohini" is not used) and charms Bhasmasura. The female Vishnu asks Bhasmasura to promise never to leave her by placing his hand on his head as per the usual practice to swear on one's head. On doing so, Bhasmasura is reduced to ashes.

In a similar legend related to the birth of Ayyappa, the demon Surpanaka earns the power to turn anyone into ashes by his austerities. The tale mirrors all other aspects of the Buddhist version of the Bhasmasura tale, where he is forced by Mohini to severe fidelity by keeping his hand on his head and is burnt.