Thero (Pali; also appearing in stem-form as thera, feminine therī) is an honorific term for bhikkhus and bhikkhunis (Buddhist monks and nuns) in the Buddhist monastic order. The Pāli term means "elder". These terms, which are used at the end of a monastic's monastic name, are useful to distinguish those who have at least 10 years since their upasampada (higher ordination). The name of an important collection of very early poetry is called the Therigatha "verses of the therīs".

The term mahāthera, feminine mahātherī, is used sometimes to refer most elderly and venerable monks who have reached a higher level of spiritual development.

Usage of these terms varies according to the Buddhist tradition and culture. In Sri Lanka, these terms are widely used.

Some prominent theras and therīs:

See also