Sister-wife is a Valyrian term which refers to a woman who is both the sister and wife of her husband. This form of incest is considered immoral and illegal by many societies, including the mainstream society of Westeros, but was commonplace in Valyria and continued to be practised by the Targaryens after they had conquered Westeros, although it remained outlawed for all others.

Known sister-wives of House TargaryenEdit