Theano of Crotone (; Greek: Θεανώ) was a 6th-century BC Pythagorean philosopher. She has been called the wife or student of Pythagoras, although others see her as the wife of Brontinus. Her place of birth and the identity of her father are uncertain as well. Some authors have suggested that there was more than one person whose details have become merged (these are sometimes referred to as Theano I and Theano II). Theano is considered by some to be the first known woman mathematician. She may have worked on The Golden Mean and The Golden Rectangle.