Remy Hadley, played by Olivia Wilde, is known by the nickname Thirteen in House M.D.
Thirteen earns the nickname because she is assigned number 13 during the selection process for House’s new diagnostic fellows. The label remains associated with her even after her identity and medical background become known.
Hadley is a physician who joins House’s team and becomes one of its most prominent members. Her storyline includes her family history, bisexuality, and Huntington’s disease risk, which gives the character a sustained personal connection to the uncertainties explored in the show’s medical cases.
Olivia Wilde played the role from the fourth season onward, with later appearances after her main run. The character’s formal name is Remy Hadley, so “Thirteen” is a nickname rather than her legal name or medical specialty.