Chanakya (ISO: Cāṇakya, चाणक्य, pronunciation^ⓘ), according to legendary narratives preserved in various traditions dating from the 4th to 11th century CE, was a Brahmin who assisted the first Mauryan emperor Chandragupta in his rise to power and the establishment of the Maurya Empire. According to these narratives, Chanakya served as the chief adviser and prime minister to both emperors Chandragupta Maurya and his son Bindusara.

Conventionally, Chanakya was identified with Kauṭilya and synonymously Vishnugupta, the author of the ancient Indian politico-economic treatise Arthashastra. Arthashastra is now thought with high probability to have been composed by multiple authors during the early centuries of the common era—several centuries after the Mauryan period—the backdated identification with Chanakya to have served to add prestige to the work.

There is no documented historical information about Chanakya: narratives about him come from legendary accounts. Thomas Trautmann identifies four distinct accounts of the ancient Chanakya-Chandragupta katha (legend):

In all the four versions, Chanakya feels insulted by the Nanda king, and vows to destroy him. After dethroning the Nanda, he installs Chandragupta as the new king.

The legend of Chanakya and Chandragupta is detailed in the Pali-language Buddhist chronicles of Sri Lanka. It is not mentioned in Dipavamsa, the oldest of these chronicles. The earliest Buddhist source to mention the legend is Mahavamsa, which is generally dated between fifth and sixth centuries CE. Vamsatthappakasini (also known as Mahvamsa Tika), a commentary on Mahavamsa, provides some more details about the legend. Its author is unknown, and it is dated variously from sixth century CE to 13th century CE. Some other texts provide additional details about the legend; for example, the Maha-Bodhi-Vamsa and the Atthakatha give the names of the nine Nanda kings said to have preceded Chandragupta.

According to the Buddhist legend, the Nanda emperors who preceded Chandragupta were robbers-turned-rulers. Chanakya (IAST: Cāṇakka in Mahavamsa) was a Brahmin from Takkāsila (Takshashila). He was well-versed in three Vedas and politics. He was born with canine teeth, which were believed to be a mark of royalty. His mother feared that he would neglect her after becoming an emperor. To pacify her, Chanakya broke his teeth.

Chanakya had an ugly appearance, accentuated by his broken teeth and crooked feet. One day, the Emperor Dhana Nanda organized an alms-giving ceremony for Brahmins. Chanakya went to Pupphapura (Pushpapura) to attend this ceremony. Disgusted by his appearance, the emperor ordered him to be thrown out of the assembly. Chanakya broke his sacred thread in anger, and cursed the emperor. The emperor ordered his arrest, but Chanakya escaped in the disguise of an Ājīvika. He befriended Dhananada's son Pabbata, and instigated him to seize the throne. With help of a signet ring given by the prince, Chanakya fled the palace through a secret door.

Chanakya escaped to the Vinjha forest. There, he made 800 million gold coins (kahapanas), using a secret technique that allowed him to turn 1 coin into 8 coins. After hiding this money, he started searching for a person worthy of replacing Dhana Nanda. One day, he saw a group of children playing: the young Chandragupta (called Chandagutta in Mahavamsa) played the role of an emperor, while other boys pretended to be vassals, ministers, or robbers. The "robbers" were brought before Chandragupta, who ordered their limbs to be cut off, but then miraculously re-attached them. Chandragupta had been born in a royal family, but was brought up by a hunter after his father was killed by an usurper, and the devatas caused his mother to abandon him. Astonished by the boy's miraculous powers, Chanakya paid 1000 gold coins to his foster-father, and took Chandragupta away, promising to teach him a trade.