Blythe House is Gregory House's biological mother and widow of John House. She is the favorite of his two parents. She was seen in season two's Daddy's Boy, season five's Birthmarks, and season eight's Love is Blind. She is portrayed by actress Diane Baker.
Blythe is portrayed as a loving and caring mother, and is one of the few characters House feels he cannot complain about. In the episode Birthmarks, Lisa Cuddy tells House that if he does not plan on attending his father, John House's funeral, he should call her and lie to her, telling her that he was too busy to attend. House says he cannot do this, for his mother can always see through his lies. House often calls his mother on holidays, and his father is seemingly the only reason he avoids them.
However, Blythe stood by her husband, John, even when he was abusive to their son. As stated in One Day, One Room, his father was extremely cruel towards House. In Birthmarks, House states that at the age of twelve, he deduced John was not his biological father, but was instead conceived from an affair between her mother and a friend of the family with a similar birthmark on his scalp. In response to his twelve-year-old son asking about this, John House didn't speak to him for two months, instead choosing to ignore him and, if he must, slip typed notes under his bedroom door.
She is one of the only characters House does not mind referring to him as "Greg" (the other being Stacy Warner).
When her husband died, she met House at his funeral. When House went to give a eulogy for his father, he said that he left success unrewarded and would punish failure. He also admitted that if it wasn't for him, House wouldn't be the kind of person he was that day. Blythe felt saddened and shocked at the same time at her son's words.
Blythe returns in Love is Blind to tell her son about her new husband, whom House had always suspected to be his biological father.
She later attends her sons funeral in Everybody Dies and says he was a good son.