Maggie Siff (born June 21, 1974) is an American actress. She is best known for her television roles as department store heiress Rachel Menken Katz on the AMC drama Mad Men and ultimately famous for her role of Dr. Tara Knowles-Teller on the FX drama Sons of Anarchy. She also had roles in the films Push (2009) as Teresa Stowe and Leaves of Grass (2010) as Rabbi Renannah Zimmerman.
She is now currently seen playing Wendy Rhoades in Showtime's finance drama Billions (2016-present).
Siff started appearing in television series in 2004. She appeared as an Alcoholics Anonymous speaker during an episode of Rescue Me in Season 2. She also had roles on Law & Order: Special Victims Unit, Grey's Anatomy, and Law & Order.