Allison Brooks Janney (born November 19, 1959) is an American actress, best known for her role as C. J. Cregg on the television series The West Wing.

Janney was born in Dayton, Ohio, the daughter of Macy (née Putnam), a former actress and homemaker, and Jervis Spencer Janney, Jr., a real estate developer and jazz musician. She has two older brothers, Jay and Hal. She attended The Miami Valley School in Dayton, where she was named a distinguished alumna in 2004, and the Hotchkiss School in Connecticut. She then attended Kenyon College. At Kenyon, Janney studied under another Kenyon alum, Paul Newman. She went on to study drama at the Neighborhood Playhouse in New York and the Royal Academy of Dramatic Arts in London. She attended The Neighborhood Playhouse the same years as actor Dylan McDermott.

Janney's first roles on television were as comedic foils on soap operas: she first played Vi Kaminski for a short time on As the World Turns, following up with a two-year stint as one of the Spaulding maids, Ginger on Guiding Light. In the spring of 1994, she appeared in the season finale of Law & Order, as a reluctant witness against a member of the Russian mob. This episode was also notable as Michael Moriarty's final episode in the series.