Devadatta (Sanskrit and Pali: देवदत्त devadatta; Sinhalese: දේවදත්ත; Burmese: ဒေဝဒတ်; Thai: เทวทัต Thewathat; Lao: ເທວະທັດ; Chinese: 提婆達多; Japanese: 提婆達多 Daibadatta; Vietnamese: Đề-Bà-Đạt-Đa) was by tradition a Buddhist monk, cousin and brother-in-law of Gautama Siddhārtha, the Sākyamuni Buddha, and brother of Ānanda, a principal student of the Buddha. Devadatta was a koliyan and sakyan and is said to have parted from the Buddha's following with 500 other monks to form their own Sangha, most of whom are said to have been Shakya clan relatives of both Devadatta and Siddhartha.
The name Devadatta has the meaning god-given in Palī and Sanskrit (cf. Latin Deodatus, Deusdedit; both also meaning god-given). It is composed from the stem form of deva and the past participle datta of the verb da, give, composed as a tatpurusa compound. In the Bhagavad Gītā, the conch shell used by Arjuna on the battle-field of Kurukshetra was named Devadatta. The name Devadatta is still given today.
According to Andrew Skilton, modern scholarship generally agrees that the Mahāsāṃghika Vinaya is the oldest extant Buddhist Vinaya. According to Reginald Ray, the Mahāsāṃghika Vinaya mentions the figure of Devadatta, but in a way that is different from the vinayas of the Sthaviravāda branch. According to this study, the earliest vinaya material common to all sects simply depicts Devadatta as a Buddhist saint who wishes for the monks to live a rigorous lifestyle. This has led Ray to regard the story of Devadatta as a legend produced by the Sthavira group. However, upon examining the same vinaya materials, Bhikkhu Sujato has written that the portrayals of Devadatta are largely consistent between the Mahāsāṃghika Vinaya and other vinayas, and that the supposed discrepancy is simply due to the minimalist literary style of the Mahāsāṃghika Vinaya. He also points to other parts of the same vinaya that clearly portray Devadatta as a villain, as well as similar portrayals that exist in the Lokottaravādin Mahāvastu.