Shorter Sukhāvatīvyūha Sūtra in the context of "Infinite Life Sutra"

The Amitāyus Sutra (Sanskrit), simplified Chinese: 佛说无量寿经; traditional Chinese: 佛說無量壽經; pinyin: Fóshuō Wúliàngshòu Jīng; Sutra of Immeasurable Life Spoken by Buddha; Vietnamese: Phật Thuyết Vô Lượng Thọ Kinh; Japanese: Bussetsu Muryōju Kyō (Taisho Tripitaka no. 360), also known as the Longer Sukhāvatīvyūha Sūtra, is one of the two Indian Mahayana sutras which describe the pure land of Amitābha (also known as Amitāyus, "Measureless Life"). Together with the Sukhāvatīvyūha Sūtra, this text is highly influential in East Asian Buddhism. It is one of the three central scriptures of East Asian Pure Land Buddhism, and is widely revered and chanted by Pure Land Buddhists throughout Asia.

The title is often translated in English as either the Sutra [on the Buddha] of Immeasurable Life, or simply the Immeasurable Life Sutra.

Pure Land Buddhism or the Pure Land School (Chinese: 淨土宗; pinyin: Jìngtǔzōng) is a broad branch of Mahayana Buddhism focused on achieving rebirth in a Pure Land. It is one of the most widely practiced traditions of Buddhism in East Asia. It is also known as the "Lotus School" (Chinese: 蓮宗; pinyin: Liánzōng) in China or the "Nembutsu school" in Japan. East Asian Pure Land mainly relies on three main Mahayana scriptures: the Sutra of Amitayus, the Contemplation Sutra and the Amitabha Sutra.

The Pure Land tradition is primarily focused on achieving rebirth in a Buddha's "pure land", a superior place to spiritually train for full Buddhahood, where one can meet a Buddha face to face and study under them without any of the distractions or fears of our world. Since it is much easier to attain enlightenment in Pure Land, many Mahayana Buddhists strive to be reborn in one. The most popular one today is Sukhavati ("Land of Bliss"), the Pure Land of Buddha Amitābha, though some Buddhists may also aspire to be reborn in other Pure Lands (such as Maitreya's and Medicine Guru's). Although Buddhas are venerated in Pure Land and are seen as savior-like figures, the tradition clearly distinguishes itself from theistic religions, due to its roots in the classic Mahayana understanding of Buddhahood and bodhisattvas, as well as the Buddhist doctrines of emptiness and mind-only.