Luminous mind (Skt: prabhāsvara-citta or ābhāsvara-citta, Pali: pabhassara citta; Tib: འོད་གསལ་གྱི་སེམས་ ’od gsal gyi sems; Ch: 光明心 guangmingxin; Jpn: 光明心 kōmyōshin) is a Buddhist term that appears only rarely in the Pali Canon, but is common in the Mahayana sūtras and central to the Buddhist tantras. It is variously translated as "brightly shining mind" or "mind of clear light", while the related term luminosity (Skt. prabhāsvaratā; Tib. འོད་གསལ་བ་ ’od gsal ba; Ch. guāng míng; Jpn. kōmyō; Kor. kwangmyōng) is also translated as "clear light" or "luminosity" in Tibetan Buddhist contexts or "purity" in East Asian contexts.

The Theravada school identifies the "luminous mind" with the bhavanga, a concept first proposed in the Theravāda Abhidhamma. The later schools of the Mahayana identify it with bodhicitta and tathagatagarbha. The luminosity of mind is of central importance in the philosophy and practice of the Buddhist tantras, Mahamudra, and Dzogchen.

The Early Buddhist Texts contain mentions of luminosity or radiance that refer to the development of the mind in meditation. In the Saṅgīti-sutta, for example, it relates to the attainment of samadhi, where the perception of light (āloka sañña) leads to a mind endowed with luminescence (sappabhāsa).

According to Anālayo, the Upakkilesa-sutta and its parallels mention that the presence of defilements "results in a loss of whatever inner light or luminescence (obhāsa) had been experienced during meditation". The Pali Dhātuvibhaṅga-sutta uses the metaphor of refining gold to describe equanimity reached through meditation, which is said to be "pure, bright, soft, workable, and luminous". The Chinese parallel to this text does not describe equanimity as luminous. Anālayo sees this difference as due to the propensity of the reciters of the Theravada canon to prefer fire and light imagery.

The Pali Anguttara Nikaya (A.I.8-10) states:

Luminous, monks, is the mind. And it is freed from incoming defilements. The well-instructed disciple of the noble ones discerns that as it actually is present, which is why I tell you that—for the well-instructed disciple of the noble ones—there is development of the mind.

A parallel passage can be found in the Śāriputrābhidharma, an Abhidharma treatise possibly of the Dharmaguptaka tradition.

Another mention of a similar term in the Pali discourses occurs in the Brahmanimantaṇika-sutta of the Majjhima-nikāya, and in the Kevaḍḍha-sutta of the Dīgha-nikāya, the latter has a parallel in a Dharmaguptaka collection surviving in Chinese translation.