Gladys is Billy's mother and Harold's wife. She is a loving, tolerant, and patient, yet mentally unstable woman. This is brought on by having to deal with her family, and Grim as an eternal guest. Gladys has reddish-orange hair and is usually seen wearing a floor-length, lavender dress. She considers Grim a constant threat to her son's safety. In multiple instances, Gladys is seen attacking Grim to protect her son. She has a severe facial tic, which usually appears when Billy is misbehaving, when her authority is challenged, or whenever Grim is present, and has also developed nervous breakdowns. Despite so, Gladys cares deeply for Billy and Harold, although when Harold gets fired for doing something so stupid or whenever Billy is really disobeying her or acting up, she does have large outbursts of rage. She wants Billy to grow up to be a chiropractor, even though she knows that is very unlikely to happen. She is prone to small fits of insanity and obsessive-compulsive episodes. Because of all of the stress caused by Billy, Harold, Grim and, to a lesser extent, Mandy, Gladys is the only character in the series to demonstrate having more control over herself when Mandy uses her own strong willpower.