The Bhadrakalpikasūtra (Full Sanskrit: Āryabhadrakalpikanāmamahāyānasūtra, Wylie: ’phags pa bskal pa bzang po zhes bya ba theg pa chen po’i mdo, The Noble Great Vehicle Sūtra “The Good Eon”) is a Mahāyāna sutra which discusses the names and deeds of over one thousand Buddhas of this "Fortunate Aeon" (bhadra kalpa). Most of the Buddhas in this sutra are future Buddhas, thus the sutra provides a future Buddhological long history of our world system.

The sutra contains 24 chapters and dates to around 200-250 CE. The sutra is the first sutra in the Kangyur's general sutra section and is one of the longest sutras translated into Tibetan. Other parallel versions of the sutra are available in Middle Chinese, Middle Mongol, and the Saka language in variants that differ slightly as to the number of Buddhas. For example, the Khotanese version has one thousand and five Buddhas.

In 2017, United States Representative Colleen Hanabusa was sworn in on an English-translated copy of the Bhadrakalpikasūtra.

The original Indic text is now lost, though fragments in Gandhari and Sanskrit do survive. One early Chinese translation of the Bhadrakalpikasūtra was done by Dharmarakṣa, a native of Dunhuang, between third and fourth centuries. However, according to Peter Skilling, this version is incomplete. That the thousand Buddha motif was popular in the Dunhuang region is evidenced by the "Thousand-Buddha Cave", which are world-renowned grottoes at Dunhuang. Various lists of thousand Buddhas have also been found in Khotanese sources, verifying the importance of this narrative theme for the Buddhist Iranian Kingdom of Khotan. Ajanta Cave no. II also includes epigraphic evidence for the idea of the one thousand Buddhas.

The Indian Vidyākarasiṃha and the Tibetan Dpal-dbyans translated the text into Old Tibetan in the 8th century, during the early translation era.

The theme of the "good eon" (Skt.: bhadrakalpa, Pali: bhaddakappa) is found in earlier sources, such as the Mahāvadāna sũtra (Pali: DN 14, Mahāpadāna sutta) sutra, in which the Buddha states. "In this very Fortunate Eon, four truly and fully Awakened Ones arise in the world: Krakasunda, Kanakamuni, Kāśyapa, and myself, Śākyamuni, at present. This is the nature of things."

According to Skilling, the idea that one thousand Buddhas will arise in this good eon "circulated in the north and northwest of the Indian subcontinent by the beginning of the Christian era, if not earlier." The idea of one thousand Buddhas is also mentioned in the Mahāvastu. Various schools had different ideas about this. Some held that just five Buddhas will arise in this eon, others that five hundred Buddhas will arise, which seems to have been common in some Sarvāstivāda circles, and others held that one thousand Buddhas will arise. Numerous Mahayana sutras mention the idea of one thousand Buddhas in this good eon, including the Lotus Sutra, the Vimalakirti Sutra, and the Śūraṅgama Samādhi Sūtra.

The Bhadrakalpikasūtra depicts the names and circumstances of the one thousand and four (1004) Buddhas of this current eon. The frame narrative states that sutra was taught by Shakyamuni Buddha in Vaiśālī on the request of Bodhisattva Prāmodyarāja. In the frame narrative, the Buddha states that far in the past, a monarch (which was a past life of the Akṣobhya Buddha) helped a Dharma teacher who was the Amitābha Buddha. As a result of the good merit of this, the monarch and his thousand sons spend eighty eons serving over three billion (3,000,000,000) Buddhas.