Theano (; ) was the priestess of Athena in Troy.
Theano (; ; fl. 6th-century BC), or Theano of Crotone, is the name given to perhaps two Pythagorean philosophers. She has been called the pupil, daughter and wife of Pythagoras, although others made her the wife of Brontinus. Her place of birth and the identity of her father are just as uncertain, leading some authors to suggest that there was more than one person whose details have become merged (these are sometimes referred to as Theano I and Theano II). A few fragments and letters ascribed to her have survived which are of uncertain authorship.
Theano may refer to:
- Theano , Ancient Greek given name:
- Theano, name of several figures in Greek mythology
- Theano, one of the Leuctrides
- Theano (philosopher), historical female philosopher
- Theano (software), a numerical computational library