Molly Shannon is an American actress and writer.

Before Saturday Night Live, Shannon had a struggling career in films. She first portrayed a supporting role as Meg in the present day sequences in the horror film remake of The Phantom of the Opera with Robert Englund and Jill Scholen.

Shannon's major break came in February of 1995 when she was hired as a featured player on Saturday Night Live to replace the departing Janeane Garofalo. She played various parts on the comedy show and was especially known for playing the character of Catholic school girl Mary Katherine Gallagher as well as her impression of Monica Lewinsky (alongside frequent host John Goodman's Linda Tripp).

After her departure from SNL in 2001 (she passed Victoria Jackson to become the show's longest-serving female cast member), Shannon has refocused on her film career. In 1999 she revisited the role of Mary Katherine Gallagher for the motion picture Superstar, and had a supporting role in Never Been Kissed. Her recent films include How the Grinch Stole Christmas, Shallow Hal, The Santa Clause 2, Serendipity and Osmosis Jones.