Maggie Siff (born June 21, 1974) is an American actress best known for her television roles, notably department-store heiress Rachel Menken Katz on the AMC drama Mad Men and Dr. Tara Knowles on the FX drama Sons of Anarchy. She also played a role in the 2009 film Push, as Teresa Stowe and in the 2010 film Leaves of Grass as Rabbi Renannah Zimmerman.