Theodore Raymond "T.R." Knight (born March 26, 1973) is an Emmy Award-nominated and Screen Actors Guild Award-winning American actor. Knight's most high-profile role to date was his role as Dr. George O'Malley on ABC's top-rated medical drama Grey's Anatomy.

Knight was born in Minneapolis, Minnesota, where he became involved with the Guthrie Theater at the age of five. Knight received the Conners Foundation Scholarship as a freshman. After finishing high school at the Academy of Holy Angels in Richfield, Knight enrolled at the University of Minnesota for a brief period of time. He dropped out and soon landed leading roles at the Guthrie Theater.

Knight moved to New York City and has appeared on Broadway; his most notable role was playing opposite Patti LuPone in the 2001 revival of Noises Off. He also gained notice performing in 2003 as Damis in Tartuffe and received a Drama Desk Award nomination in 2003 for his role in the off-Broadway production of Scattergood. Knight's most recent stage appearance was in the 2004 drama, Boy.