Ermengarde of Tours was a 9th-century Carolingian empress and queen of Italy. Born around 804 to Hugh of Tours and Ava of Morvois, she married the Frankish Emperor Lothair I in 821 at Thionville. As a member of the imperial family, she had several children, including Louis II of Italy and various daughters who held positions as abbesses. She died in 851 in Erstein, where she was laid to rest.