DeDe Pritchett is Jay Pritchett's ex-wife and the mother of Claire Dunphy and Mitchell Pritchett, and grandmother of Haley, Alex, Luke and Lily. She caused a scene at his wedding, which is referred to as The Incident. She later apologizes to Gloria, but tries to hit her moments later.
It is implied that she was initially more accepting of Mitchell's sexual orientation than Jay was when he first came out. She often uses her close relationship with Mitchell to get him to do things she doesn't want to. She is still bitter over Jay's re-marriage to Gloria and even attempted to ruin their wedding, which she convinced Mitchell to invite her to, by getting drunk and making rude and inappropriate toasts, and eventually had to be dragged out of the reception. She is also passive aggressive toward Cameron about his weight, and is often critical of Claire.