Quackmore Duck is the husband of Hortense McDuck, the father of Donald Duck and Della Duck, the son of Humperdink Duck and Elvira Duck, the brother-in-law of Scrooge McDuck and Matilda McDuck, the nephew-in-law of Angus McDuck and Jacob "Jake" McDuck, the grandson-in-law of Dingus McDuck and Molly McDuck, the son-in-law of Fergus McDuck and Downy McDuck, and also the maternal grandfather of Huey, Dewey, and Louie Duck.