thumb|260px|The Complete Enlightenment Sutra, gold on oak paper
thumb|Illustration for the sutra, Korea, 14th century
The Sutra of Perfect Enlightenment or Complete Enlightenment () is a Mahāyāna Buddhist sūtra highly esteemed by both the Huayan and Chan/Zen schools.
Divided into twelve chapters as a series of discussions on meditation practice, this text deals with issues such as the meaning and origin of ignorance, sudden and gradual enlightenment, original Buddhahood, etc. these themes were also elucidated in the Awakening of Faith. It was intended to resolve questions regarding doctrine and meditation for the earliest practitioners of the Chan school. One of the most important and important commentaries written on it is the 9th-century Great Exegesis on the Sutra of Complete Enlightenment (圓覺經大疏鈔 Yuanjuejing Dashuchao) by the Huayan Patriarch Guifeng Zongmi (圭峰宗密, 780–841).
Titles
Its full Chinese title: (, ).
Its reconstructed title in Sanskrit is Mahāvaipulya pūrṇabuddha-sūtra prasannārtha-sūtra.